iOS Browsers

(default settings)
brave logo
brave
1.62
chrome logo
chrome
122.6261
duckduckgo logo
duckduckgo
7.109
edge logo
edge
121.2277
firefox logo
firefox
123.1
focus logo
focus
123.0
opera logo
opera
4.5
safari logo
safari
17.3
vivaldi logo
vivaldi
6.3212
yandex logo
yandex
2401.5
State Partitioning testsWhich browsers isolate websites to prevent them from sharing data to track you?
A common vulnerability of web browsers is that they allow tracking companies to 'tag' your browser with some data ('state') that identifies you. When third-party trackers are embedded in websites, they can see this identifying data as you browse to different websites. Fortunately, it is possible for this category of leaks to be fixed by partitioning all data stored in the browser such that no data can be shared between websites.
        
Alt-Svc
Alt-Svc allows the server to indicate to the web browser that a resource should be loaded on a different server. Because this is a persistent setting, it could be used to track users across websites if it is not correctly partitioned.
              
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: h3, h3, h3, h3, h3

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Passed
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
h3,
Error: Unsupported,
Error: Unsupported

result, different first party: h3, h3, h2, h3, h3

unsupported: true, true, false, true, true

passed: , true

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: h3, h3, h3, h3, h3

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: h3, h3, h3, h3, h3

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: h3, h3, h3, h3, h3

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: h3, h3, h3, h2, h3

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Passed
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
h3,
Error: Unsupported

result, different first party: h3, h3, h3, h2, h3

unsupported: true, true, true, false, true

passed: , true

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: h2, h3, h3, h3, h3

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: h3, h3, h3, h3, h3

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same first party: Error: Unsupported

result, different first party: h3

unsupported: true

passed: undefined

test failed: false
blob
A 'blob URL' is a local reference to some raw data. Trackers can use a blob URL to share data between websites.
              
Passed
write: (secret) => {
      try {
        let blobURL = URL.createObjectURL(new Blob([secret]));
        fetch(`${baseURI}blob?mode=write&key=${secret}&blobUrl=${encodeURIComponent(blobURL)}`);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async (secret) => {
      let response = await fetch(`${baseURI}blob?mode=read&key=${secret}`);
      let result = await response.json();
      let blobUrl = decodeURIComponent(result.blobUrl);
      let blobResponse = await fetch(blobUrl);
      return blobResponse.text();
    }

result, same first party: 
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed

result, different first party: 
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: (secret) => {
      try {
        let blobURL = URL.createObjectURL(new Blob([secret]));
        fetch(`${baseURI}blob?mode=write&key=${secret}&blobUrl=${encodeURIComponent(blobURL)}`);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async (secret) => {
      let response = await fetch(`${baseURI}blob?mode=read&key=${secret}`);
      let result = await response.json();
      let blobUrl = decodeURIComponent(result.blobUrl);
      let blobResponse = await fetch(blobUrl);
      return blobResponse.text();
    }

result, same first party: 
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed

result, different first party: 
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: (secret) => {
      try {
        let blobURL = URL.createObjectURL(new Blob([secret]));
        fetch(`${baseURI}blob?mode=write&key=${secret}&blobUrl=${encodeURIComponent(blobURL)}`);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async (secret) => {
      let response = await fetch(`${baseURI}blob?mode=read&key=${secret}`);
      let result = await response.json();
      let blobUrl = decodeURIComponent(result.blobUrl);
      let blobResponse = await fetch(blobUrl);
      return blobResponse.text();
    }

result, same first party: 
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed

result, different first party: 
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: (secret) => {
      try {
        let blobURL = URL.createObjectURL(new Blob([secret]));
        fetch(`${baseURI}blob?mode=write&key=${secret}&blobUrl=${encodeURIComponent(blobURL)}`);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async (secret) => {
      let response = await fetch(`${baseURI}blob?mode=read&key=${secret}`);
      let result = await response.json();
      let blobUrl = decodeURIComponent(result.blobUrl);
      let blobResponse = await fetch(blobUrl);
      return blobResponse.text();
    }

result, same first party: 
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed

result, different first party: 
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: (secret) => {
      try {
        let blobURL = URL.createObjectURL(new Blob([secret]));
        fetch(`${baseURI}blob?mode=write&key=${secret}&blobUrl=${encodeURIComponent(blobURL)}`);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async (secret) => {
      let response = await fetch(`${baseURI}blob?mode=read&key=${secret}`);
      let result = await response.json();
      let blobUrl = decodeURIComponent(result.blobUrl);
      let blobResponse = await fetch(blobUrl);
      return blobResponse.text();
    }

result, same first party: 
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed

result, different first party: 
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: (secret) => {
      try {
        let blobURL = URL.createObjectURL(new Blob([secret]));
        fetch(`${baseURI}blob?mode=write&key=${secret}&blobUrl=${encodeURIComponent(blobURL)}`);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async (secret) => {
      let response = await fetch(`${baseURI}blob?mode=read&key=${secret}`);
      let result = await response.json();
      let blobUrl = decodeURIComponent(result.blobUrl);
      let blobResponse = await fetch(blobUrl);
      return blobResponse.text();
    }

result, same first party: 
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed

result, different first party: 
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: (secret) => {
      try {
        let blobURL = URL.createObjectURL(new Blob([secret]));
        fetch(`${baseURI}blob?mode=write&key=${secret}&blobUrl=${encodeURIComponent(blobURL)}`);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async (secret) => {
      let response = await fetch(`${baseURI}blob?mode=read&key=${secret}`);
      let result = await response.json();
      let blobUrl = decodeURIComponent(result.blobUrl);
      let blobResponse = await fetch(blobUrl);
      return blobResponse.text();
    }

result, same first party: 
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed

result, different first party: 
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: (secret) => {
      try {
        let blobURL = URL.createObjectURL(new Blob([secret]));
        fetch(`${baseURI}blob?mode=write&key=${secret}&blobUrl=${encodeURIComponent(blobURL)}`);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async (secret) => {
      let response = await fetch(`${baseURI}blob?mode=read&key=${secret}`);
      let result = await response.json();
      let blobUrl = decodeURIComponent(result.blobUrl);
      let blobResponse = await fetch(blobUrl);
      return blobResponse.text();
    }

result, same first party: 
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed

result, different first party: 
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: (secret) => {
      try {
        let blobURL = URL.createObjectURL(new Blob([secret]));
        fetch(`${baseURI}blob?mode=write&key=${secret}&blobUrl=${encodeURIComponent(blobURL)}`);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async (secret) => {
      let response = await fetch(`${baseURI}blob?mode=read&key=${secret}`);
      let result = await response.json();
      let blobUrl = decodeURIComponent(result.blobUrl);
      let blobResponse = await fetch(blobUrl);
      return blobResponse.text();
    }

result, same first party: 
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed

result, different first party: 
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed,
Error: Load failed

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: (secret) => {
      try {
        let blobURL = URL.createObjectURL(new Blob([secret]));
        fetch(`${baseURI}blob?mode=write&key=${secret}&blobUrl=${encodeURIComponent(blobURL)}`);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async (secret) => {
      let response = await fetch(`${baseURI}blob?mode=read&key=${secret}`);
      let result = await response.json();
      let blobUrl = decodeURIComponent(result.blobUrl);
      let blobResponse = await fetch(blobUrl);
      return blobResponse.text();
    }

result, same first party: Error: Load failed

result, different first party: Error: Load failed

unsupported: false

passed: undefined

test failed: true
BroadcastChannel
A BroadcastChannel is designed to send messages between tabs. In some browsers it can be used for cross-site communication and tracking.
              
Passed
write: (secret) => {
      try {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data === "request") {
            bc.postMessage(secret);
          }
        };
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () =>
      new Promise((resolve, reject) => {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data !== "request") {
            resolve(event.data);
          }
        };
        bc.postMessage("request");
        setTimeout(() => reject({message: "no BroadcastChannel message"}), 3000);
      })

result, same first party: 
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message

result, different first party: 
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: (secret) => {
      try {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data === "request") {
            bc.postMessage(secret);
          }
        };
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () =>
      new Promise((resolve, reject) => {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data !== "request") {
            resolve(event.data);
          }
        };
        bc.postMessage("request");
        setTimeout(() => reject({message: "no BroadcastChannel message"}), 3000);
      })

result, same first party: 
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message

result, different first party: 
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: (secret) => {
      try {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data === "request") {
            bc.postMessage(secret);
          }
        };
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () =>
      new Promise((resolve, reject) => {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data !== "request") {
            resolve(event.data);
          }
        };
        bc.postMessage("request");
        setTimeout(() => reject({message: "no BroadcastChannel message"}), 3000);
      })

result, same first party: 
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message

result, different first party: 
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: (secret) => {
      try {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data === "request") {
            bc.postMessage(secret);
          }
        };
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () =>
      new Promise((resolve, reject) => {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data !== "request") {
            resolve(event.data);
          }
        };
        bc.postMessage("request");
        setTimeout(() => reject({message: "no BroadcastChannel message"}), 3000);
      })

result, same first party: 
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message

result, different first party: 
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: (secret) => {
      try {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data === "request") {
            bc.postMessage(secret);
          }
        };
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () =>
      new Promise((resolve, reject) => {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data !== "request") {
            resolve(event.data);
          }
        };
        bc.postMessage("request");
        setTimeout(() => reject({message: "no BroadcastChannel message"}), 3000);
      })

result, same first party: 
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message

result, different first party: 
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: (secret) => {
      try {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data === "request") {
            bc.postMessage(secret);
          }
        };
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () =>
      new Promise((resolve, reject) => {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data !== "request") {
            resolve(event.data);
          }
        };
        bc.postMessage("request");
        setTimeout(() => reject({message: "no BroadcastChannel message"}), 3000);
      })

result, same first party: 
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message

result, different first party: 
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: (secret) => {
      try {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data === "request") {
            bc.postMessage(secret);
          }
        };
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () =>
      new Promise((resolve, reject) => {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data !== "request") {
            resolve(event.data);
          }
        };
        bc.postMessage("request");
        setTimeout(() => reject({message: "no BroadcastChannel message"}), 3000);
      })

result, same first party: 
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message

result, different first party: 
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: (secret) => {
      try {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data === "request") {
            bc.postMessage(secret);
          }
        };
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () =>
      new Promise((resolve, reject) => {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data !== "request") {
            resolve(event.data);
          }
        };
        bc.postMessage("request");
        setTimeout(() => reject({message: "no BroadcastChannel message"}), 3000);
      })

result, same first party: 
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message

result, different first party: 
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: (secret) => {
      try {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data === "request") {
            bc.postMessage(secret);
          }
        };
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () =>
      new Promise((resolve, reject) => {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data !== "request") {
            resolve(event.data);
          }
        };
        bc.postMessage("request");
        setTimeout(() => reject({message: "no BroadcastChannel message"}), 3000);
      })

result, same first party: 
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message

result, different first party: 
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message,
Error: no BroadcastChannel message

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: (secret) => {
      try {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data === "request") {
            bc.postMessage(secret);
          }
        };
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () =>
      new Promise((resolve, reject) => {
        let bc = new BroadcastChannel("secrets");
        bc.onmessage = (event) => {
          if (event.data !== "request") {
            resolve(event.data);
          }
        };
        bc.postMessage("request");
        setTimeout(() => reject({message: "no BroadcastChannel message"}), 3000);
      })

result, same first party: Error: no BroadcastChannel message

result, different first party: Error: no BroadcastChannel message

unsupported: false

passed: undefined

test failed: true
CacheStorage
The Cache API is a content storage mechanism originally introduced to support ServiceWorkers. If the same Cache object is accessible to multiple websites, it can be abused to track users.
              
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same first party: 
4bde1512-0784-43fb-887a-56a509216ec5,
41005147-8107-4a0f-bd00-5de04892fc40,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1,
bcde0d87-19c8-4d11-b69d-cf5b05adac32,
cf7b9801-6b0c-4efc-9361-c923491dbafc

result, different first party: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same first party: 
6ff0b878-e459-4077-873d-c4d73a8b4c3f,
94d0ff49-2e50-4f68-a576-2f481a9b0dfb,
db9ededa-3d85-49d1-b22f-66b9d13151e9,
eda356c0-dfbb-48c4-98bc-e3060f20796d,
45855e06-c12b-4c97-a80f-b05d0634705e

result, different first party: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same first party: 
c846cb44-12d2-41b3-b2a6-38ca1a4518ed,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed

result, different first party: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same first party: 
9f1a20c0-3f9c-4aa5-8aa8-e56950e57e74,
e4fef07d-00dc-4960-8421-eaed44851eed,
154af211-304d-45c2-bd1d-edfcf6a953c2,
bbc94382-8354-43fa-9caa-06c72e77a772,
5cd2be12-be84-4ee2-ad4f-e8bd13d52186

result, different first party: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same first party: 
a09b69c9-0216-4504-9061-fc5c61dd3c23,
7b6315a4-06ef-4ac0-8f42-ce400041b707,
2d5c9ed0-3dbd-48e7-84ef-eb6e8484cdbf,
65902525-09ad-4c46-865a-d3fc1f63ac7b,
6e3bb471-c66f-4f24-8437-1dbee8645c0e

result, different first party: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same first party: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

result, different first party: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same first party: 
213faa81-9820-4e64-8ca2-4b2c56e0fd16,
cf7391f7-aa80-401f-81c4-7c2508844631,
6cb5025c-2699-446a-9372-39087b296a21,
9a0e433f-dc60-4ba4-ba79-fa1ff3caccb5,
4335c2dd-8867-446f-8184-bd81aa0654b6

result, different first party: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same first party: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

result, different first party: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same first party: 
b4e6c154-78d4-4ea8-9de8-7342f2b90461,
a938646f-4e8a-409b-8a23-9aa66b47e388,
26e63861-906d-420b-bba7-f80b45898c34,
cda34f43-1255-481b-9e0d-1c216b86d6fa,
6779afe3-026e-4315-87e0-9c8f43f3c72c

result, different first party: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same first party: 40268717-416c-4353-9311-83b6625eb429

result, different first party: Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false

passed: true

test failed: false
cookie (HTTP)
The cookie, first introduced by Netscape in 1994, is a small amount of data stored by your browser on a website's behalf. It has legitimate uses, but it is also the classic cross-site tracking mechanism, and today still the most popular method of tracking users across websites. Browsers can stop cookies from being used for cross-site tracking by either blocking or partitioning them.
              
Passed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same first party: 
4bde1512-0784-43fb-887a-56a509216ec5_http,
41005147-8107-4a0f-bd00-5de04892fc40_http,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1_http,
bcde0d87-19c8-4d11-b69d-cf5b05adac32_http,
cf7b9801-6b0c-4efc-9361-c923491dbafc_http

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same first party: 
6ff0b878-e459-4077-873d-c4d73a8b4c3f_http,
94d0ff49-2e50-4f68-a576-2f481a9b0dfb_http,
db9ededa-3d85-49d1-b22f-66b9d13151e9_http,
eda356c0-dfbb-48c4-98bc-e3060f20796d_http,
45855e06-c12b-4c97-a80f-b05d0634705e_http

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same first party: 
58109673-6b30-4c3c-93dc-9f3935edeced_http,
2aa2bf6f-0a07-4a35-ae45-e9b6a1d11e20_http,
732a589c-ffa1-441f-b046-e96ae5ecce3b_http,
be322cbd-9046-492a-8283-325c7e6e36ca_http,
4d80e8ed-2942-4e43-80e6-7e11a7e16883_http

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same first party: 
9f1a20c0-3f9c-4aa5-8aa8-e56950e57e74_http,
e4fef07d-00dc-4960-8421-eaed44851eed_http,
154af211-304d-45c2-bd1d-edfcf6a953c2_http,
bbc94382-8354-43fa-9caa-06c72e77a772_http,
5cd2be12-be84-4ee2-ad4f-e8bd13d52186_http

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same first party: 
a09b69c9-0216-4504-9061-fc5c61dd3c23_http,
7b6315a4-06ef-4ac0-8f42-ce400041b707_http,
2d5c9ed0-3dbd-48e7-84ef-eb6e8484cdbf_http,
65902525-09ad-4c46-865a-d3fc1f63ac7b_http,
6e3bb471-c66f-4f24-8437-1dbee8645c0e_http

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same first party: 
c4e8c0f1-6882-4a88-b2b0-1abda72db45e_http,
ae52c0dc-9b2c-4efd-9348-d816b188d956_http,
9d44a7cf-1964-4a73-81b3-b7941a1a8e4d_http,
3a9a3eda-7e51-42b7-9ccf-5557bf5b9c77_http,
896b9c56-96e4-44cb-9a3b-76bd875cead7_http

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same first party: 
213faa81-9820-4e64-8ca2-4b2c56e0fd16_http,
cf7391f7-aa80-401f-81c4-7c2508844631_http,
6cb5025c-2699-446a-9372-39087b296a21_http,
9a0e433f-dc60-4ba4-ba79-fa1ff3caccb5_http,
4335c2dd-8867-446f-8184-bd81aa0654b6_http

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same first party: 
1e854cf6-6d0d-4987-b89f-4f0e6bfb3013_http,
2485a3ce-aa3e-4197-ba4a-2835da79e7ac_http,
f8e56e03-da27-4aae-9eee-18c4b864da6a_http,
63fc99e9-1362-4918-9b98-fd62c233cfaf_http,
7fe7e385-59f1-4ded-a894-f9710f27446e_http

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same first party: 
b4e6c154-78d4-4ea8-9de8-7342f2b90461_http,
a938646f-4e8a-409b-8a23-9aa66b47e388_http,
26e63861-906d-420b-bba7-f80b45898c34_http,
cda34f43-1255-481b-9e0d-1c216b86d6fa_http,
6779afe3-026e-4315-87e0-9c8f43f3c72c_http

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same first party: 40268717-416c-4353-9311-83b6625eb429_http

result, different first party: null

unsupported: false

passed: true

test failed: false
cookie (JS)
The cookie, first introduced by Netscape in 1994, is a small amount of data stored by your browser on a website's behalf. It has legitimate uses, but it is also the classic cross-site tracking mechanism, and today still the most popular method of tracking users across websites. Browsers can stop cookies from being used for cross-site tracking by either blocking or partitioning them.
              
Passed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same first party: 
4bde1512-0784-43fb-887a-56a509216ec5_js,
41005147-8107-4a0f-bd00-5de04892fc40_js,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1_js,
bcde0d87-19c8-4d11-b69d-cf5b05adac32_js,
cf7b9801-6b0c-4efc-9361-c923491dbafc_js

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same first party: 
6ff0b878-e459-4077-873d-c4d73a8b4c3f_js,
94d0ff49-2e50-4f68-a576-2f481a9b0dfb_js,
db9ededa-3d85-49d1-b22f-66b9d13151e9_js,
eda356c0-dfbb-48c4-98bc-e3060f20796d_js,
45855e06-c12b-4c97-a80f-b05d0634705e_js

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same first party: 
58109673-6b30-4c3c-93dc-9f3935edeced_js,
2aa2bf6f-0a07-4a35-ae45-e9b6a1d11e20_js,
732a589c-ffa1-441f-b046-e96ae5ecce3b_js,
be322cbd-9046-492a-8283-325c7e6e36ca_js,
4d80e8ed-2942-4e43-80e6-7e11a7e16883_js

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same first party: 
9f1a20c0-3f9c-4aa5-8aa8-e56950e57e74_js,
e4fef07d-00dc-4960-8421-eaed44851eed_js,
154af211-304d-45c2-bd1d-edfcf6a953c2_js,
bbc94382-8354-43fa-9caa-06c72e77a772_js,
5cd2be12-be84-4ee2-ad4f-e8bd13d52186_js

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same first party: 
a09b69c9-0216-4504-9061-fc5c61dd3c23_js,
7b6315a4-06ef-4ac0-8f42-ce400041b707_js,
2d5c9ed0-3dbd-48e7-84ef-eb6e8484cdbf_js,
65902525-09ad-4c46-865a-d3fc1f63ac7b_js,
6e3bb471-c66f-4f24-8437-1dbee8645c0e_js

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same first party: 
c4e8c0f1-6882-4a88-b2b0-1abda72db45e_js,
ae52c0dc-9b2c-4efd-9348-d816b188d956_js,
9d44a7cf-1964-4a73-81b3-b7941a1a8e4d_js,
3a9a3eda-7e51-42b7-9ccf-5557bf5b9c77_js,
896b9c56-96e4-44cb-9a3b-76bd875cead7_js

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same first party: 
213faa81-9820-4e64-8ca2-4b2c56e0fd16_js,
cf7391f7-aa80-401f-81c4-7c2508844631_js,
6cb5025c-2699-446a-9372-39087b296a21_js,
9a0e433f-dc60-4ba4-ba79-fa1ff3caccb5_js,
4335c2dd-8867-446f-8184-bd81aa0654b6_js

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same first party: 
1e854cf6-6d0d-4987-b89f-4f0e6bfb3013_js,
2485a3ce-aa3e-4197-ba4a-2835da79e7ac_js,
f8e56e03-da27-4aae-9eee-18c4b864da6a_js,
63fc99e9-1362-4918-9b98-fd62c233cfaf_js,
7fe7e385-59f1-4ded-a894-f9710f27446e_js

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same first party: 
b4e6c154-78d4-4ea8-9de8-7342f2b90461_js,
a938646f-4e8a-409b-8a23-9aa66b47e388_js,
26e63861-906d-420b-bba7-f80b45898c34_js,
cda34f43-1255-481b-9e0d-1c216b86d6fa_js,
6779afe3-026e-4315-87e0-9c8f43f3c72c_js

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same first party: 40268717-416c-4353-9311-83b6625eb429_js

result, different first party: null

unsupported: false

passed: true

test failed: false
CookieStore
The Cookie Store API is an alternative asynchronous API for managing cookies, supported by some browsers.
              
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same first party: Error: Unsupported

result, different first party: Error: Unsupported

unsupported: true

passed: undefined

test failed: false
CSS cache
CSS stylesheets are cached, and if that cache is shared between websites, it can be used to track users across sites.
              
Passed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same first party: 
fake_023286531788832665,
fake_8462541920099718,
fake_6890561456491442,
fake_9536754532575809,
fake_10305489321662287

result, different first party: 
fake_06422546220212766,
fake_23036080268318515,
fake_9073864017266182,
fake_30348058686522195,
fake_008422977672478682

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same first party: 
fake_9900087116704399,
fake_2028165219234157,
fake_5650060431040007,
fake_42783992068667787,
fake_41522064103127554

result, different first party: 
fake_24241696928850653,
fake_5024762771462588,
fake_5845638541172562,
fake_12635960577521854,
fake_606057200227615

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same first party: 
fake_1695273045617134,
fake_675574827092436,
fake_7464822738105421,
fake_24244748173022534,
fake_9190767452957951

result, different first party: 
fake_09372667800975387,
fake_2512358597564792,
fake_8775949026000234,
fake_01050147291008785,
fake_39697198926210264

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same first party: 
fake_7670009559633109,
fake_28786126705763593,
fake_8787607803789981,
fake_5763756992394893,
fake_639461929955996

result, different first party: 
fake_1426975545212832,
fake_6356879059136056,
fake_8934693967481768,
fake_7216378062830497,
fake_7091531976209431

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same first party: 
fake_9184568098200827,
fake_5034571493880295,
fake_005314657508014076,
fake_5429343210520325,
fake_004779960670068917

result, different first party: 
fake_2028450474247816,
fake_7789329563439149,
fake_991131743435731,
fake_40737057402457366,
fake_5137477214818271

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same first party: 
fake_8106264569238506,
fake_8315950338972744,
fake_892674560526612,
fake_3457800409202665,
fake_5905103914390928

result, different first party: 
fake_5947410008132465,
fake_7986605463267062,
fake_5253889266724137,
fake_8315003738973763,
fake_785609308207575

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same first party: 
fake_5612488971627372,
fake_8822504293928048,
fake_5995845426810211,
fake_14463143007451262,
fake_29509333230230284

result, different first party: 
fake_5492407608426284,
fake_9933778951738033,
fake_5645562830712842,
fake_9990362835835385,
fake_19984099520052534

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same first party: 
fake_8998001876923656,
fake_8540015068101829,
fake_6137505339371903,
fake_7281655649141312,
fake_9349190122110513

result, different first party: 
fake_7544275186982226,
fake_6337765684617875,
fake_6948644700525979,
fake_5924367476102763,
fake_1569368527263746

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same first party: 
fake_7481212350099038,
fake_19402542278981216,
fake_5693208405426282,
fake_2549487174286158,
fake_8662397720162234

result, different first party: 
fake_4115536930064796,
fake_7698580297121993,
fake_29603435656793087,
fake_42133844132768283,
fake_4052307284460508

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same first party: fake_2622304635363861

result, different first party: fake_5553626461493733

unsupported: false

passed: true

test failed: false
favicon cache
A favicon is an icon that represents a website, typically shown in browser tab and bookmarks menu. If the favicon cache is not partitioned, it can be used to track users across websites.
              
Failed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Unsupported
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Failed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Unsupported
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Failed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same first party: 2, 2, 1, 2, 2

result, different first party: 2, 2, 1, 2, 2

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same first party: 1

result, different first party: 1

unsupported: false

passed: false

test failed: false
fetch cache
When a resource is received via the Fetch API, it is frequently cached. That cache can potentially be abused for cross-site tracking.
              
Passed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 1

result, different first party: 2

unsupported: false

passed: true

test failed: false
font cache
Web fonts are sometimes stored in their own cache, which is vulnerable to being abused for cross-site tracking.
              
Passed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2

result, different first party: 3

unsupported: false

passed: true

test failed: false
getDirectory
navigator.storage.getDirectory exposes a location for storing files to web content. In some cases, these files may be shared across tabs.
              
Unsupported
write: async (secret) => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt", { create: true });
        const stream = await fileHandle.createWritable();
        await stream.write(secret);
        await stream.close();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt");
        const file = await fileHandle.getFile();
        return file.text();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

result, same first party: , , , , 

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt", { create: true });
        const stream = await fileHandle.createWritable();
        await stream.write(secret);
        await stream.close();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt");
        const file = await fileHandle.getFile();
        return file.text();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

result, same first party: , , , , 

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt", { create: true });
        const stream = await fileHandle.createWritable();
        await stream.write(secret);
        await stream.close();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt");
        const file = await fileHandle.getFile();
        return file.text();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

result, same first party: , , , , 

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt", { create: true });
        const stream = await fileHandle.createWritable();
        await stream.write(secret);
        await stream.close();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt");
        const file = await fileHandle.getFile();
        return file.text();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

result, same first party: , , , , 

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt", { create: true });
        const stream = await fileHandle.createWritable();
        await stream.write(secret);
        await stream.close();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt");
        const file = await fileHandle.getFile();
        return file.text();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

result, same first party: , , , , 

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt", { create: true });
        const stream = await fileHandle.createWritable();
        await stream.write(secret);
        await stream.close();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt");
        const file = await fileHandle.getFile();
        return file.text();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt", { create: true });
        const stream = await fileHandle.createWritable();
        await stream.write(secret);
        await stream.close();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt");
        const file = await fileHandle.getFile();
        return file.text();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

result, same first party: , , , , 

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt", { create: true });
        const stream = await fileHandle.createWritable();
        await stream.write(secret);
        await stream.close();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt");
        const file = await fileHandle.getFile();
        return file.text();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt", { create: true });
        const stream = await fileHandle.createWritable();
        await stream.write(secret);
        await stream.close();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt");
        const file = await fileHandle.getFile();
        return file.text();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

result, same first party: , , , , 

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt", { create: true });
        const stream = await fileHandle.createWritable();
        await stream.write(secret);
        await stream.close();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      try {
        const root = await navigator.storage.getDirectory();
        const fileHandle = await root.getFileHandle("secret.txt");
        const file = await fileHandle.getFile();
        return file.text();
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

result, same first party: 

result, different first party: Error: Unsupported

unsupported: true

passed: undefined

test failed: false
H1 connection
HTTP/1.x are the classic web connection protocols. If these connections are re-used across websites, they can be used to track users.
              
Passed
write: async (secret) => {
      await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h1.privacytests2.org:8901/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 
4bde1512-0784-43fb-887a-56a509216ec5,
41005147-8107-4a0f-bd00-5de04892fc40,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1,
bcde0d87-19c8-4d11-b69d-cf5b05adac32,
cf7b9801-6b0c-4efc-9361-c923491dbafc

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h1.privacytests2.org:8901/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 
6ff0b878-e459-4077-873d-c4d73a8b4c3f,
94d0ff49-2e50-4f68-a576-2f481a9b0dfb,
db9ededa-3d85-49d1-b22f-66b9d13151e9,
eda356c0-dfbb-48c4-98bc-e3060f20796d,
45855e06-c12b-4c97-a80f-b05d0634705e

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h1.privacytests2.org:8901/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 
58109673-6b30-4c3c-93dc-9f3935edeced,
2aa2bf6f-0a07-4a35-ae45-e9b6a1d11e20,
732a589c-ffa1-441f-b046-e96ae5ecce3b,
be322cbd-9046-492a-8283-325c7e6e36ca,
4d80e8ed-2942-4e43-80e6-7e11a7e16883

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h1.privacytests2.org:8901/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 
9f1a20c0-3f9c-4aa5-8aa8-e56950e57e74,
e4fef07d-00dc-4960-8421-eaed44851eed,
154af211-304d-45c2-bd1d-edfcf6a953c2,
bbc94382-8354-43fa-9caa-06c72e77a772,
5cd2be12-be84-4ee2-ad4f-e8bd13d52186

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h1.privacytests2.org:8901/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 
a09b69c9-0216-4504-9061-fc5c61dd3c23,
7b6315a4-06ef-4ac0-8f42-ce400041b707,
2d5c9ed0-3dbd-48e7-84ef-eb6e8484cdbf,
65902525-09ad-4c46-865a-d3fc1f63ac7b,
6e3bb471-c66f-4f24-8437-1dbee8645c0e

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h1.privacytests2.org:8901/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 
c4e8c0f1-6882-4a88-b2b0-1abda72db45e,
ae52c0dc-9b2c-4efd-9348-d816b188d956,
9d44a7cf-1964-4a73-81b3-b7941a1a8e4d,
3a9a3eda-7e51-42b7-9ccf-5557bf5b9c77,
896b9c56-96e4-44cb-9a3b-76bd875cead7

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h1.privacytests2.org:8901/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 
213faa81-9820-4e64-8ca2-4b2c56e0fd16,
cf7391f7-aa80-401f-81c4-7c2508844631,
6cb5025c-2699-446a-9372-39087b296a21,
9a0e433f-dc60-4ba4-ba79-fa1ff3caccb5,
4335c2dd-8867-446f-8184-bd81aa0654b6

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h1.privacytests2.org:8901/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 
1e854cf6-6d0d-4987-b89f-4f0e6bfb3013,
2485a3ce-aa3e-4197-ba4a-2835da79e7ac,
f8e56e03-da27-4aae-9eee-18c4b864da6a,
63fc99e9-1362-4918-9b98-fd62c233cfaf,
7fe7e385-59f1-4ded-a894-f9710f27446e

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h1.privacytests2.org:8901/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 
b4e6c154-78d4-4ea8-9de8-7342f2b90461,
a938646f-4e8a-409b-8a23-9aa66b47e388,
26e63861-906d-420b-bba7-f80b45898c34,
cda34f43-1255-481b-9e0d-1c216b86d6fa,
6779afe3-026e-4315-87e0-9c8f43f3c72c

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h1.privacytests2.org:8901/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 40268717-416c-4353-9311-83b6625eb429

result, different first party: 

unsupported: false

passed: true

test failed: false
H2 connection
HTTP/2 is a web connection protocol introduced in 2015. Some browsers re-use HTTP/2 connections across websites and can thus be used to track users.
              
Passed
write: async (secret) => {
      await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h2.privacytests2.org:8902/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 
4bde1512-0784-43fb-887a-56a509216ec5,
41005147-8107-4a0f-bd00-5de04892fc40,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1,
bcde0d87-19c8-4d11-b69d-cf5b05adac32,
cf7b9801-6b0c-4efc-9361-c923491dbafc

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h2.privacytests2.org:8902/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 
6ff0b878-e459-4077-873d-c4d73a8b4c3f,
94d0ff49-2e50-4f68-a576-2f481a9b0dfb,
db9ededa-3d85-49d1-b22f-66b9d13151e9,
eda356c0-dfbb-48c4-98bc-e3060f20796d,
45855e06-c12b-4c97-a80f-b05d0634705e

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h2.privacytests2.org:8902/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 
58109673-6b30-4c3c-93dc-9f3935edeced,
2aa2bf6f-0a07-4a35-ae45-e9b6a1d11e20,
732a589c-ffa1-441f-b046-e96ae5ecce3b,
be322cbd-9046-492a-8283-325c7e6e36ca,
4d80e8ed-2942-4e43-80e6-7e11a7e16883

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h2.privacytests2.org:8902/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 
9f1a20c0-3f9c-4aa5-8aa8-e56950e57e74,
e4fef07d-00dc-4960-8421-eaed44851eed,
154af211-304d-45c2-bd1d-edfcf6a953c2,
bbc94382-8354-43fa-9caa-06c72e77a772,
5cd2be12-be84-4ee2-ad4f-e8bd13d52186

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h2.privacytests2.org:8902/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 
a09b69c9-0216-4504-9061-fc5c61dd3c23,
7b6315a4-06ef-4ac0-8f42-ce400041b707,
2d5c9ed0-3dbd-48e7-84ef-eb6e8484cdbf,
65902525-09ad-4c46-865a-d3fc1f63ac7b,
6e3bb471-c66f-4f24-8437-1dbee8645c0e

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h2.privacytests2.org:8902/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 
c4e8c0f1-6882-4a88-b2b0-1abda72db45e,
ae52c0dc-9b2c-4efd-9348-d816b188d956,
9d44a7cf-1964-4a73-81b3-b7941a1a8e4d,
3a9a3eda-7e51-42b7-9ccf-5557bf5b9c77,
896b9c56-96e4-44cb-9a3b-76bd875cead7

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h2.privacytests2.org:8902/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 
213faa81-9820-4e64-8ca2-4b2c56e0fd16,
cf7391f7-aa80-401f-81c4-7c2508844631,
6cb5025c-2699-446a-9372-39087b296a21,
9a0e433f-dc60-4ba4-ba79-fa1ff3caccb5,
4335c2dd-8867-446f-8184-bd81aa0654b6

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h2.privacytests2.org:8902/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 
1e854cf6-6d0d-4987-b89f-4f0e6bfb3013,
2485a3ce-aa3e-4197-ba4a-2835da79e7ac,
f8e56e03-da27-4aae-9eee-18c4b864da6a,
63fc99e9-1362-4918-9b98-fd62c233cfaf,
7fe7e385-59f1-4ded-a894-f9710f27446e

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h2.privacytests2.org:8902/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 
b4e6c154-78d4-4ea8-9de8-7342f2b90461,
a938646f-4e8a-409b-8a23-9aa66b47e388,
26e63861-906d-420b-bba7-f80b45898c34,
cda34f43-1255-481b-9e0d-1c216b86d6fa,
6779afe3-026e-4315-87e0-9c8f43f3c72c

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${secret}`, {cache: "no-store"});
    }

read: async () => {
      let response = await fetch(`https://h2.privacytests2.org:8902/?mode=read`, {cache: "no-store"});
      return await response.text();
    }

result, same first party: 40268717-416c-4353-9311-83b6625eb429

result, different first party: 

unsupported: false

passed: true

test failed: false
H3 connection
HTTP/3 is a new standard HTTP connection protocol, still in draft but widely supported by browsers. If it is not partitioned, it can be used to track users across websites.
              
Passed
write: async (secret) => {
      // Ensure that we can switch over to h3 via alt-svc:
      for (let i = 0; i<3; ++i) {
        await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
        await sleepMs(500);
      }
      // Are we now connecting over h3?
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
      let text = await response.text();
      // Empty response text indicates we are not connecting over h3:
      if (text.trim() === "") {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`);
      return await response.text();
    }

result, same first party: , b62b73ccfe7e4f26fbc944448385d4ec, aba689eb09d34051046db0a807a6ea3f, 1a680d01d964ba1a4fb5e13e06244f6b, b79a94c4223150e327f32d8eae818195

result, different first party: , a33d40ca03f4b92aace7fabaf6acf78d, 134a409fa15a370ccf2742b28519cedc, ccee3293f7779602ed47ac9721688c65, 9cb8340229f7bce46a42d92d6f1fc318

unsupported: true, false, false, false, false

passed: , true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      // Ensure that we can switch over to h3 via alt-svc:
      for (let i = 0; i<3; ++i) {
        await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
        await sleepMs(500);
      }
      // Are we now connecting over h3?
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
      let text = await response.text();
      // Empty response text indicates we are not connecting over h3:
      if (text.trim() === "") {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`);
      return await response.text();
    }

result, same first party: , a73b83b8bc51bcb892a48e0b1033494e, 60fc80455edee50256e08ddec2ce590b, 3fa06eec5a57510f2612f106099b2de9, fa4c403282bab079af69b53ca3bdd010

result, different first party: , cd7b5090ee5445b5ca100969887d59b3, , d702623110421ad57f0885344036f0b3, c55408795d5dde7382da95c0d3e60d52

unsupported: true, false, false, false, false

passed: , true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      // Ensure that we can switch over to h3 via alt-svc:
      for (let i = 0; i<3; ++i) {
        await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
        await sleepMs(500);
      }
      // Are we now connecting over h3?
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
      let text = await response.text();
      // Empty response text indicates we are not connecting over h3:
      if (text.trim() === "") {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`);
      return await response.text();
    }

result, same first party: , 2069a27252da55ec98227bde94af7294, 422623bb277e36b1106a5a314502a9ff, 4143141a7329ec2aa92a03a5401cfc08, 71e8b46fa7ab6eb34a3b5cf9bbb53378

result, different first party: , 59248f6c94cd8ee15f5aaf448b717f9e, 8d738c8bed48ed514fcabbed318d3d7c, 0bbd8619618e69467e5a2449174ed628, 7832f047ea8813ee851ab521e9d3d8b4

unsupported: true, false, false, false, false

passed: , true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      // Ensure that we can switch over to h3 via alt-svc:
      for (let i = 0; i<3; ++i) {
        await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
        await sleepMs(500);
      }
      // Are we now connecting over h3?
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
      let text = await response.text();
      // Empty response text indicates we are not connecting over h3:
      if (text.trim() === "") {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`);
      return await response.text();
    }

result, same first party: , 100b48bb2a1c63812a8456d54905d10b, 3f5eff42234d35c2f11b9b2eac26f9ff, 5a9f6eb2e1dd1a51a65c3f3f3c20f08d, 90763c2b295907a25f4d8bb4dd8bf513

result, different first party: , b1d7dbd1dadb2ae19d1f2bee2dd4575f, a6a4a5a1445d8587b4d0f87a6b39f264, 65d905d3877f0528d86c3a8b9656b4f5, e1e774b437ee1e12ce7eabaaa37c58ab

unsupported: true, false, false, false, false

passed: , true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      // Ensure that we can switch over to h3 via alt-svc:
      for (let i = 0; i<3; ++i) {
        await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
        await sleepMs(500);
      }
      // Are we now connecting over h3?
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
      let text = await response.text();
      // Empty response text indicates we are not connecting over h3:
      if (text.trim() === "") {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`);
      return await response.text();
    }

result, same first party: 
844b8160b38a955e09f57bfcd8c2a852,
f1f86664d89b7df92aa68fe32f599d09,
d2e5ce6d469bf72a7e5f860c72083b3d,
8cf4b6f7be14880cbdfff1aa9736d27d,
dc92769d4a3f756001920fbb187590f8

result, different first party: 
8288310be5cd9e0ea7f3e3b22c2bd98a,
4af05cac495313f20dd7ec7a5d4ccdb5,
ba2414836f763621c031ca567c27dcc6,
78158d79ee02307b6331b23fef98f099,
02bf16cb047e466bdd2ea5fe540ad450

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      // Ensure that we can switch over to h3 via alt-svc:
      for (let i = 0; i<3; ++i) {
        await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
        await sleepMs(500);
      }
      // Are we now connecting over h3?
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
      let text = await response.text();
      // Empty response text indicates we are not connecting over h3:
      if (text.trim() === "") {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`);
      return await response.text();
    }

result, same first party: , , , , 

result, different first party: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      // Ensure that we can switch over to h3 via alt-svc:
      for (let i = 0; i<3; ++i) {
        await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
        await sleepMs(500);
      }
      // Are we now connecting over h3?
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
      let text = await response.text();
      // Empty response text indicates we are not connecting over h3:
      if (text.trim() === "") {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`);
      return await response.text();
    }

result, same first party: , 85819bcfa682569441cf6985c8af553d, 15dc424ccaecdc6b3722037939187cd0, 85c2ad8d43a1806ce5512be9f69e57bb, ff06ef0ba75f35f81a78c01b90ae4c26

result, different first party: , 2e0285a4d83aacf1021762ae02ac91f7, 8028d1a882793668f5600594fceee2bc, , d173469540cd72da8e6dd1c490b76b2f

unsupported: true, false, false, false, false

passed: , true, true, true, true

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      // Ensure that we can switch over to h3 via alt-svc:
      for (let i = 0; i<3; ++i) {
        await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
        await sleepMs(500);
      }
      // Are we now connecting over h3?
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
      let text = await response.text();
      // Empty response text indicates we are not connecting over h3:
      if (text.trim() === "") {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`);
      return await response.text();
    }

result, same first party: , , , , 

result, different first party: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      // Ensure that we can switch over to h3 via alt-svc:
      for (let i = 0; i<3; ++i) {
        await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
        await sleepMs(500);
      }
      // Are we now connecting over h3?
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
      let text = await response.text();
      // Empty response text indicates we are not connecting over h3:
      if (text.trim() === "") {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`);
      return await response.text();
    }

result, same first party: , 78f3baa97a7f60546ff2362e53c10c65, 3fcf7737fb9d875b2733baa15c3f278b, 05093da620f9de9edfa04f4bd26d6343, 288955f7712186cbc015576bb40d98f3

result, different first party: , 331dc4d4d4fbd2264c9b8bf568d88589, 255803669271968e590445d824b67192, 868fcaf1bb9a327324fdf7cb45fa6214, 52f5718a6ffc04ae02f24b8d381a2204

unsupported: true, false, false, false, false

passed: , true, true, true, true

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      // Ensure that we can switch over to h3 via alt-svc:
      for (let i = 0; i<3; ++i) {
        await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
        await sleepMs(500);
      }
      // Are we now connecting over h3?
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`, {cache: "no-store"});
      let text = await response.text();
      // Empty response text indicates we are not connecting over h3:
      if (text.trim() === "") {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let response = await fetch(`https://h3.privacytests2.org:4434/connection_id`);
      return await response.text();
    }

result, same first party: 

result, different first party: 

unsupported: true

passed: undefined

test failed: false
HSTS cache
The HTTP Strict-Transport-Security response header allows a website to signal that it should only be accessed via HTTPS. The browser remembers this directive in a database, but if this database is not partitioned, then it can be used to track users across websites."
              
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested, not tested, not tested, not tested, not tested

result, different first party: Used http, Used http, Used http, Used http, Used http

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested, not tested, not tested, not tested, not tested

result, different first party: Used http, Used http, Used http, Used http, Used http

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested, not tested, not tested, not tested, not tested

result, different first party: Used http, Used http, Used http, Used http, Used http

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested, not tested, not tested, not tested, not tested

result, different first party: Used http, Used http, Used http, Used http, Used http

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested, not tested, not tested, not tested, not tested

result, different first party: Used http, Used http, Used http, Used http, Used http

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested, not tested, not tested, not tested, not tested

result, different first party: Used http, Used http, Used http, Used http, Used http

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested, not tested, not tested, not tested, not tested

result, different first party: Used http, Used http, Used http, Used http, Used http

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested, not tested, not tested, not tested, not tested

result, different first party: Used http, Used http, Used http, Used http, Used http

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested, not tested, not tested, not tested, not tested

result, different first party: Used http, Used http, Used http, Used http, Used http

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested

result, different first party: Used http

unsupported: false

passed: true

test failed: false
HSTS cache (fetch)
The HTTP Strict-Transport-Security response header allows a website to signal that it should only be accessed via HTTPS. The browser remembers this directive in a database, but if this database is not partitioned, then it can be used to track users across websites."
              
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested, not tested, not tested, not tested, not tested

result, different first party: Used http, Used http, Used http, Used http, Used http

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested, not tested, not tested, not tested, not tested

result, different first party: Used http, Used http, Used http, Used http, Used http

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested, not tested, not tested, not tested, not tested

result, different first party: Used http, Used http, Used http, Used http, Used http

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested, not tested, not tested, not tested, not tested

result, different first party: Used http, Used http, Used http, Used http, Used http

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested, not tested, not tested, not tested, not tested

result, different first party: Used http, Used http, Used http, Used http, Used http

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested, not tested, not tested, not tested, not tested

result, different first party: Used http, Used http, Used http, Used http, Used http

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested, not tested, not tested, not tested, not tested

result, different first party: Used http, Used http, Used http, Used http, Used http

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested, not tested, not tested, not tested, not tested

result, different first party: Used http, Used http, Used http, Used http, Used http

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested, not tested, not tested, not tested, not tested

result, different first party: Used http, Used http, Used http, Used http, Used http

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: set HSTS flag

read: read HSTS flag

result, same first party: not tested

result, different first party: Used http

unsupported: false

passed: true

test failed: false
iframe cache
An iframe is an element in a web page than allows websites to embed a second web page. Caching of this web page could be abused for cross-site tracking.
              
Passed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 1

result, different first party: 2

unsupported: false

passed: true

test failed: false
image cache
Caching of images in web browsers is a standard behavior. But if that cache leaks between websites, it can be abused for cross-site tracking.
              
Passed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2

result, different first party: 3

unsupported: false

passed: true

test failed: false
indexedDB
The IndexedDB API exposes a transactional database to web pages. That database can be used to track users across websites, unless it is partitioned.
              
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same first party: 
4bde1512-0784-43fb-887a-56a509216ec5,
41005147-8107-4a0f-bd00-5de04892fc40,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1,
bcde0d87-19c8-4d11-b69d-cf5b05adac32,
cf7b9801-6b0c-4efc-9361-c923491dbafc

result, different first party: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same first party: 
6ff0b878-e459-4077-873d-c4d73a8b4c3f,
94d0ff49-2e50-4f68-a576-2f481a9b0dfb,
db9ededa-3d85-49d1-b22f-66b9d13151e9,
eda356c0-dfbb-48c4-98bc-e3060f20796d,
45855e06-c12b-4c97-a80f-b05d0634705e

result, different first party: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same first party: 
58109673-6b30-4c3c-93dc-9f3935edeced,
2aa2bf6f-0a07-4a35-ae45-e9b6a1d11e20,
732a589c-ffa1-441f-b046-e96ae5ecce3b,
be322cbd-9046-492a-8283-325c7e6e36ca,
4d80e8ed-2942-4e43-80e6-7e11a7e16883

result, different first party: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same first party: 
9f1a20c0-3f9c-4aa5-8aa8-e56950e57e74,
e4fef07d-00dc-4960-8421-eaed44851eed,
154af211-304d-45c2-bd1d-edfcf6a953c2,
bbc94382-8354-43fa-9caa-06c72e77a772,
5cd2be12-be84-4ee2-ad4f-e8bd13d52186

result, different first party: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same first party: 
a09b69c9-0216-4504-9061-fc5c61dd3c23,
7b6315a4-06ef-4ac0-8f42-ce400041b707,
2d5c9ed0-3dbd-48e7-84ef-eb6e8484cdbf,
65902525-09ad-4c46-865a-d3fc1f63ac7b,
6e3bb471-c66f-4f24-8437-1dbee8645c0e

result, different first party: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same first party: 
c4e8c0f1-6882-4a88-b2b0-1abda72db45e,
ae52c0dc-9b2c-4efd-9348-d816b188d956,
9d44a7cf-1964-4a73-81b3-b7941a1a8e4d,
3a9a3eda-7e51-42b7-9ccf-5557bf5b9c77,
896b9c56-96e4-44cb-9a3b-76bd875cead7

result, different first party: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same first party: 
213faa81-9820-4e64-8ca2-4b2c56e0fd16,
cf7391f7-aa80-401f-81c4-7c2508844631,
6cb5025c-2699-446a-9372-39087b296a21,
9a0e433f-dc60-4ba4-ba79-fa1ff3caccb5,
4335c2dd-8867-446f-8184-bd81aa0654b6

result, different first party: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same first party: 
1e854cf6-6d0d-4987-b89f-4f0e6bfb3013,
2485a3ce-aa3e-4197-ba4a-2835da79e7ac,
f8e56e03-da27-4aae-9eee-18c4b864da6a,
63fc99e9-1362-4918-9b98-fd62c233cfaf,
7fe7e385-59f1-4ded-a894-f9710f27446e

result, different first party: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same first party: 
b4e6c154-78d4-4ea8-9de8-7342f2b90461,
a938646f-4e8a-409b-8a23-9aa66b47e388,
26e63861-906d-420b-bba7-f80b45898c34,
cda34f43-1255-481b-9e0d-1c216b86d6fa,
6779afe3-026e-4315-87e0-9c8f43f3c72c

result, different first party: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same first party: 40268717-416c-4353-9311-83b6625eb429

result, different first party: undefined

unsupported: false

passed: true

test failed: false
localStorage
The localStorage API gives websites access to a key-value database that will remain available across visits. If the localStorage API is not partitioned or blocked, it can also be used to track users across websites.
              
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same first party: 
4bde1512-0784-43fb-887a-56a509216ec5,
41005147-8107-4a0f-bd00-5de04892fc40,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1,
bcde0d87-19c8-4d11-b69d-cf5b05adac32,
cf7b9801-6b0c-4efc-9361-c923491dbafc

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same first party: 
6ff0b878-e459-4077-873d-c4d73a8b4c3f,
94d0ff49-2e50-4f68-a576-2f481a9b0dfb,
db9ededa-3d85-49d1-b22f-66b9d13151e9,
eda356c0-dfbb-48c4-98bc-e3060f20796d,
45855e06-c12b-4c97-a80f-b05d0634705e

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same first party: 
58109673-6b30-4c3c-93dc-9f3935edeced,
2aa2bf6f-0a07-4a35-ae45-e9b6a1d11e20,
732a589c-ffa1-441f-b046-e96ae5ecce3b,
be322cbd-9046-492a-8283-325c7e6e36ca,
4d80e8ed-2942-4e43-80e6-7e11a7e16883

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same first party: 
9f1a20c0-3f9c-4aa5-8aa8-e56950e57e74,
e4fef07d-00dc-4960-8421-eaed44851eed,
154af211-304d-45c2-bd1d-edfcf6a953c2,
bbc94382-8354-43fa-9caa-06c72e77a772,
5cd2be12-be84-4ee2-ad4f-e8bd13d52186

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same first party: 
a09b69c9-0216-4504-9061-fc5c61dd3c23,
7b6315a4-06ef-4ac0-8f42-ce400041b707,
2d5c9ed0-3dbd-48e7-84ef-eb6e8484cdbf,
65902525-09ad-4c46-865a-d3fc1f63ac7b,
6e3bb471-c66f-4f24-8437-1dbee8645c0e

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same first party: 
c4e8c0f1-6882-4a88-b2b0-1abda72db45e,
ae52c0dc-9b2c-4efd-9348-d816b188d956,
9d44a7cf-1964-4a73-81b3-b7941a1a8e4d,
3a9a3eda-7e51-42b7-9ccf-5557bf5b9c77,
896b9c56-96e4-44cb-9a3b-76bd875cead7

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same first party: 
213faa81-9820-4e64-8ca2-4b2c56e0fd16,
cf7391f7-aa80-401f-81c4-7c2508844631,
6cb5025c-2699-446a-9372-39087b296a21,
9a0e433f-dc60-4ba4-ba79-fa1ff3caccb5,
4335c2dd-8867-446f-8184-bd81aa0654b6

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same first party: 
1e854cf6-6d0d-4987-b89f-4f0e6bfb3013,
2485a3ce-aa3e-4197-ba4a-2835da79e7ac,
f8e56e03-da27-4aae-9eee-18c4b864da6a,
63fc99e9-1362-4918-9b98-fd62c233cfaf,
7fe7e385-59f1-4ded-a894-f9710f27446e

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same first party: 
b4e6c154-78d4-4ea8-9de8-7342f2b90461,
a938646f-4e8a-409b-8a23-9aa66b47e388,
26e63861-906d-420b-bba7-f80b45898c34,
cda34f43-1255-481b-9e0d-1c216b86d6fa,
6779afe3-026e-4315-87e0-9c8f43f3c72c

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same first party: 40268717-416c-4353-9311-83b6625eb429

result, different first party: null

unsupported: false

passed: true

test failed: false
locks
navigator.locks (only supported in some browsers) allows scripts on multiple tabs to coordinate. If this API is not partitioned, it can be used for cross-site tracking.
              
Passed
write: async (key) => {
      if (navigator.locks) {
        navigator.locks.request(key, lock => new Promise((f,r) => {}));
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].clientId;
      } else {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      if (navigator.locks) {
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].name;
      }
    }

result, same first party: 
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name')

result, different first party: 
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name')

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      if (navigator.locks) {
        navigator.locks.request(key, lock => new Promise((f,r) => {}));
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].clientId;
      } else {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      if (navigator.locks) {
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].name;
      }
    }

result, same first party: 
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name')

result, different first party: 
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name')

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      if (navigator.locks) {
        navigator.locks.request(key, lock => new Promise((f,r) => {}));
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].clientId;
      } else {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      if (navigator.locks) {
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].name;
      }
    }

result, same first party: 
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name')

result, different first party: 
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name')

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      if (navigator.locks) {
        navigator.locks.request(key, lock => new Promise((f,r) => {}));
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].clientId;
      } else {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      if (navigator.locks) {
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].name;
      }
    }

result, same first party: 
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name')

result, different first party: 
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name')

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      if (navigator.locks) {
        navigator.locks.request(key, lock => new Promise((f,r) => {}));
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].clientId;
      } else {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      if (navigator.locks) {
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].name;
      }
    }

result, same first party: 
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name')

result, different first party: 
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name')

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      if (navigator.locks) {
        navigator.locks.request(key, lock => new Promise((f,r) => {}));
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].clientId;
      } else {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      if (navigator.locks) {
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].name;
      }
    }

result, same first party: 
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name')

result, different first party: 
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name')

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      if (navigator.locks) {
        navigator.locks.request(key, lock => new Promise((f,r) => {}));
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].clientId;
      } else {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      if (navigator.locks) {
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].name;
      }
    }

result, same first party: 
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name')

result, different first party: 
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name')

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      if (navigator.locks) {
        navigator.locks.request(key, lock => new Promise((f,r) => {}));
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].clientId;
      } else {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      if (navigator.locks) {
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].name;
      }
    }

result, same first party: 
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name')

result, different first party: 
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name')

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      if (navigator.locks) {
        navigator.locks.request(key, lock => new Promise((f,r) => {}));
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].clientId;
      } else {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      if (navigator.locks) {
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].name;
      }
    }

result, same first party: 
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name')

result, different first party: 
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name'),
Error: undefined is not an object (evaluating 'queryResult.held[0].name')

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      if (navigator.locks) {
        navigator.locks.request(key, lock => new Promise((f,r) => {}));
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].clientId;
      } else {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      if (navigator.locks) {
        let queryResult = await navigator.locks.query();
        return queryResult.held[0].name;
      }
    }

result, same first party: Error: undefined is not an object (evaluating 'queryResult.held[0].name')

result, different first party: Error: undefined is not an object (evaluating 'queryResult.held[0].name')

unsupported: false

passed: undefined

test failed: true
prefetch cache
A <link rel='prefetch'...> suggests to browsers they should fetch a resource ahead of time and cache it. But if browsers don't partition this cache, it can be used to track users across websites.
              
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different first party: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same first party: Error: No requests received

result, different first party: Error: No requests received

unsupported: true

passed: undefined

test failed: false
script cache
Caching of scripts in web browsers is a standard behavior. But if that cache leaks between websites, it can be abused for cross-site tracking.
              
Passed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same first party: 2

result, different first party: 3

unsupported: false

passed: true

test failed: false
ServiceWorker
The ServiceWorker API allows websites to run code in the background and store content in the browser for offline use. If a ServiceWorker can be accessed from multiple websites, it can be abused to track users across sites.
              
Passed
write: async (key) => {
      if (!navigator.serviceWorker) {
        throw new Error("Unsupported");
      }
      let registration = await navigator.serviceWorker.register(
        'serviceWorker.js');
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      await fetch(`serviceworker-write?secret=${key}`);
    }

read: async () => {
      console.log("trying to register the serviceworker now...");
      const registration = await Promise.race([
        navigator.serviceWorker.register('serviceWorker.js'),
        sleepMs(500)
      ]);
      if (registration === undefined) {
        // We timed out or otherwise failed.
        throw new Error("ServiceWorker registration failed");
      }
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      let response = await fetch("serviceworker-read");
      return await response.text();
    }

result, same first party: , , , , 

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      if (!navigator.serviceWorker) {
        throw new Error("Unsupported");
      }
      let registration = await navigator.serviceWorker.register(
        'serviceWorker.js');
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      await fetch(`serviceworker-write?secret=${key}`);
    }

read: async () => {
      console.log("trying to register the serviceworker now...");
      const registration = await Promise.race([
        navigator.serviceWorker.register('serviceWorker.js'),
        sleepMs(500)
      ]);
      if (registration === undefined) {
        // We timed out or otherwise failed.
        throw new Error("ServiceWorker registration failed");
      }
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      let response = await fetch("serviceworker-read");
      return await response.text();
    }

result, same first party: , , , , 

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      if (!navigator.serviceWorker) {
        throw new Error("Unsupported");
      }
      let registration = await navigator.serviceWorker.register(
        'serviceWorker.js');
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      await fetch(`serviceworker-write?secret=${key}`);
    }

read: async () => {
      console.log("trying to register the serviceworker now...");
      const registration = await Promise.race([
        navigator.serviceWorker.register('serviceWorker.js'),
        sleepMs(500)
      ]);
      if (registration === undefined) {
        // We timed out or otherwise failed.
        throw new Error("ServiceWorker registration failed");
      }
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      let response = await fetch("serviceworker-read");
      return await response.text();
    }

result, same first party: , , , , 

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      if (!navigator.serviceWorker) {
        throw new Error("Unsupported");
      }
      let registration = await navigator.serviceWorker.register(
        'serviceWorker.js');
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      await fetch(`serviceworker-write?secret=${key}`);
    }

read: async () => {
      console.log("trying to register the serviceworker now...");
      const registration = await Promise.race([
        navigator.serviceWorker.register('serviceWorker.js'),
        sleepMs(500)
      ]);
      if (registration === undefined) {
        // We timed out or otherwise failed.
        throw new Error("ServiceWorker registration failed");
      }
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      let response = await fetch("serviceworker-read");
      return await response.text();
    }

result, same first party: , , , , 

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      if (!navigator.serviceWorker) {
        throw new Error("Unsupported");
      }
      let registration = await navigator.serviceWorker.register(
        'serviceWorker.js');
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      await fetch(`serviceworker-write?secret=${key}`);
    }

read: async () => {
      console.log("trying to register the serviceworker now...");
      const registration = await Promise.race([
        navigator.serviceWorker.register('serviceWorker.js'),
        sleepMs(500)
      ]);
      if (registration === undefined) {
        // We timed out or otherwise failed.
        throw new Error("ServiceWorker registration failed");
      }
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      let response = await fetch("serviceworker-read");
      return await response.text();
    }

result, same first party: , , , , 

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      if (!navigator.serviceWorker) {
        throw new Error("Unsupported");
      }
      let registration = await navigator.serviceWorker.register(
        'serviceWorker.js');
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      await fetch(`serviceworker-write?secret=${key}`);
    }

read: async () => {
      console.log("trying to register the serviceworker now...");
      const registration = await Promise.race([
        navigator.serviceWorker.register('serviceWorker.js'),
        sleepMs(500)
      ]);
      if (registration === undefined) {
        // We timed out or otherwise failed.
        throw new Error("ServiceWorker registration failed");
      }
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      let response = await fetch("serviceworker-read");
      return await response.text();
    }

result, same first party: , , , , 

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      if (!navigator.serviceWorker) {
        throw new Error("Unsupported");
      }
      let registration = await navigator.serviceWorker.register(
        'serviceWorker.js');
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      await fetch(`serviceworker-write?secret=${key}`);
    }

read: async () => {
      console.log("trying to register the serviceworker now...");
      const registration = await Promise.race([
        navigator.serviceWorker.register('serviceWorker.js'),
        sleepMs(500)
      ]);
      if (registration === undefined) {
        // We timed out or otherwise failed.
        throw new Error("ServiceWorker registration failed");
      }
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      let response = await fetch("serviceworker-read");
      return await response.text();
    }

result, same first party: , , , , 

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      if (!navigator.serviceWorker) {
        throw new Error("Unsupported");
      }
      let registration = await navigator.serviceWorker.register(
        'serviceWorker.js');
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      await fetch(`serviceworker-write?secret=${key}`);
    }

read: async () => {
      console.log("trying to register the serviceworker now...");
      const registration = await Promise.race([
        navigator.serviceWorker.register('serviceWorker.js'),
        sleepMs(500)
      ]);
      if (registration === undefined) {
        // We timed out or otherwise failed.
        throw new Error("ServiceWorker registration failed");
      }
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      let response = await fetch("serviceworker-read");
      return await response.text();
    }

result, same first party: , , , , 

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      if (!navigator.serviceWorker) {
        throw new Error("Unsupported");
      }
      let registration = await navigator.serviceWorker.register(
        'serviceWorker.js');
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      await fetch(`serviceworker-write?secret=${key}`);
    }

read: async () => {
      console.log("trying to register the serviceworker now...");
      const registration = await Promise.race([
        navigator.serviceWorker.register('serviceWorker.js'),
        sleepMs(500)
      ]);
      if (registration === undefined) {
        // We timed out or otherwise failed.
        throw new Error("ServiceWorker registration failed");
      }
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      let response = await fetch("serviceworker-read");
      return await response.text();
    }

result, same first party: , , , , 

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: undefined

test failed: true, true, true, true, true
Passed
write: async (key) => {
      if (!navigator.serviceWorker) {
        throw new Error("Unsupported");
      }
      let registration = await navigator.serviceWorker.register(
        'serviceWorker.js');
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      await fetch(`serviceworker-write?secret=${key}`);
    }

read: async () => {
      console.log("trying to register the serviceworker now...");
      const registration = await Promise.race([
        navigator.serviceWorker.register('serviceWorker.js'),
        sleepMs(500)
      ]);
      if (registration === undefined) {
        // We timed out or otherwise failed.
        throw new Error("ServiceWorker registration failed");
      }
      console.log(registration);
      await navigator.serviceWorker.ready;
      console.log("service worker ready");
      await sleepMs(100);
      let response = await fetch("serviceworker-read");
      return await response.text();
    }

result, same first party: 

result, different first party: 

unsupported: false

passed: undefined

test failed: true
SharedWorker
The SharedWorker API allows scripts from multiple tabs to share a background thread of computation. If SharedWorker is not partitioned, then it can be abused to shared data between websites in your browser.
              
Unsupported
write: async (secret) => {
      try {
        let worker = new SharedWorker("supercookies_sharedworker.js");
        worker.port.start();
//        console.log("worker", worker);
        const messagePromise = new Promise((resolve) => {
          worker.port.onmessage = (e) => resolve(e.data);
        });
        worker.port.postMessage(secret);
        await messagePromise;
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let worker = new SharedWorker("supercookies_sharedworker.js");
      worker.port.start();
      const messagePromise = new Promise((resolve, reject) => {
        worker.port.onmessage = (e) => resolve(e.data);
        setTimeout(() => reject(new Error("no SharedWorker message received")), 200);
      });
      worker.port.postMessage("request");
      const message = await messagePromise;
      if (message === "none") {
        throw new Error("Unsupported");
      }
      return message;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      try {
        let worker = new SharedWorker("supercookies_sharedworker.js");
        worker.port.start();
//        console.log("worker", worker);
        const messagePromise = new Promise((resolve) => {
          worker.port.onmessage = (e) => resolve(e.data);
        });
        worker.port.postMessage(secret);
        await messagePromise;
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let worker = new SharedWorker("supercookies_sharedworker.js");
      worker.port.start();
      const messagePromise = new Promise((resolve, reject) => {
        worker.port.onmessage = (e) => resolve(e.data);
        setTimeout(() => reject(new Error("no SharedWorker message received")), 200);
      });
      worker.port.postMessage("request");
      const message = await messagePromise;
      if (message === "none") {
        throw new Error("Unsupported");
      }
      return message;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      try {
        let worker = new SharedWorker("supercookies_sharedworker.js");
        worker.port.start();
//        console.log("worker", worker);
        const messagePromise = new Promise((resolve) => {
          worker.port.onmessage = (e) => resolve(e.data);
        });
        worker.port.postMessage(secret);
        await messagePromise;
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let worker = new SharedWorker("supercookies_sharedworker.js");
      worker.port.start();
      const messagePromise = new Promise((resolve, reject) => {
        worker.port.onmessage = (e) => resolve(e.data);
        setTimeout(() => reject(new Error("no SharedWorker message received")), 200);
      });
      worker.port.postMessage("request");
      const message = await messagePromise;
      if (message === "none") {
        throw new Error("Unsupported");
      }
      return message;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      try {
        let worker = new SharedWorker("supercookies_sharedworker.js");
        worker.port.start();
//        console.log("worker", worker);
        const messagePromise = new Promise((resolve) => {
          worker.port.onmessage = (e) => resolve(e.data);
        });
        worker.port.postMessage(secret);
        await messagePromise;
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let worker = new SharedWorker("supercookies_sharedworker.js");
      worker.port.start();
      const messagePromise = new Promise((resolve, reject) => {
        worker.port.onmessage = (e) => resolve(e.data);
        setTimeout(() => reject(new Error("no SharedWorker message received")), 200);
      });
      worker.port.postMessage("request");
      const message = await messagePromise;
      if (message === "none") {
        throw new Error("Unsupported");
      }
      return message;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      try {
        let worker = new SharedWorker("supercookies_sharedworker.js");
        worker.port.start();
//        console.log("worker", worker);
        const messagePromise = new Promise((resolve) => {
          worker.port.onmessage = (e) => resolve(e.data);
        });
        worker.port.postMessage(secret);
        await messagePromise;
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let worker = new SharedWorker("supercookies_sharedworker.js");
      worker.port.start();
      const messagePromise = new Promise((resolve, reject) => {
        worker.port.onmessage = (e) => resolve(e.data);
        setTimeout(() => reject(new Error("no SharedWorker message received")), 200);
      });
      worker.port.postMessage("request");
      const message = await messagePromise;
      if (message === "none") {
        throw new Error("Unsupported");
      }
      return message;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      try {
        let worker = new SharedWorker("supercookies_sharedworker.js");
        worker.port.start();
//        console.log("worker", worker);
        const messagePromise = new Promise((resolve) => {
          worker.port.onmessage = (e) => resolve(e.data);
        });
        worker.port.postMessage(secret);
        await messagePromise;
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let worker = new SharedWorker("supercookies_sharedworker.js");
      worker.port.start();
      const messagePromise = new Promise((resolve, reject) => {
        worker.port.onmessage = (e) => resolve(e.data);
        setTimeout(() => reject(new Error("no SharedWorker message received")), 200);
      });
      worker.port.postMessage("request");
      const message = await messagePromise;
      if (message === "none") {
        throw new Error("Unsupported");
      }
      return message;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      try {
        let worker = new SharedWorker("supercookies_sharedworker.js");
        worker.port.start();
//        console.log("worker", worker);
        const messagePromise = new Promise((resolve) => {
          worker.port.onmessage = (e) => resolve(e.data);
        });
        worker.port.postMessage(secret);
        await messagePromise;
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let worker = new SharedWorker("supercookies_sharedworker.js");
      worker.port.start();
      const messagePromise = new Promise((resolve, reject) => {
        worker.port.onmessage = (e) => resolve(e.data);
        setTimeout(() => reject(new Error("no SharedWorker message received")), 200);
      });
      worker.port.postMessage("request");
      const message = await messagePromise;
      if (message === "none") {
        throw new Error("Unsupported");
      }
      return message;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      try {
        let worker = new SharedWorker("supercookies_sharedworker.js");
        worker.port.start();
//        console.log("worker", worker);
        const messagePromise = new Promise((resolve) => {
          worker.port.onmessage = (e) => resolve(e.data);
        });
        worker.port.postMessage(secret);
        await messagePromise;
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let worker = new SharedWorker("supercookies_sharedworker.js");
      worker.port.start();
      const messagePromise = new Promise((resolve, reject) => {
        worker.port.onmessage = (e) => resolve(e.data);
        setTimeout(() => reject(new Error("no SharedWorker message received")), 200);
      });
      worker.port.postMessage("request");
      const message = await messagePromise;
      if (message === "none") {
        throw new Error("Unsupported");
      }
      return message;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      try {
        let worker = new SharedWorker("supercookies_sharedworker.js");
        worker.port.start();
//        console.log("worker", worker);
        const messagePromise = new Promise((resolve) => {
          worker.port.onmessage = (e) => resolve(e.data);
        });
        worker.port.postMessage(secret);
        await messagePromise;
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let worker = new SharedWorker("supercookies_sharedworker.js");
      worker.port.start();
      const messagePromise = new Promise((resolve, reject) => {
        worker.port.onmessage = (e) => resolve(e.data);
        setTimeout(() => reject(new Error("no SharedWorker message received")), 200);
      });
      worker.port.postMessage("request");
      const message = await messagePromise;
      if (message === "none") {
        throw new Error("Unsupported");
      }
      return message;
    }

result, same first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different first party: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      try {
        let worker = new SharedWorker("supercookies_sharedworker.js");
        worker.port.start();
//        console.log("worker", worker);
        const messagePromise = new Promise((resolve) => {
          worker.port.onmessage = (e) => resolve(e.data);
        });
        worker.port.postMessage(secret);
        await messagePromise;
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let worker = new SharedWorker("supercookies_sharedworker.js");
      worker.port.start();
      const messagePromise = new Promise((resolve, reject) => {
        worker.port.onmessage = (e) => resolve(e.data);
        setTimeout(() => reject(new Error("no SharedWorker message received")), 200);
      });
      worker.port.postMessage("request");
      const message = await messagePromise;
      if (message === "none") {
        throw new Error("Unsupported");
      }
      return message;
    }

result, same first party: Error: Unsupported

result, different first party: Error: Unsupported

unsupported: true

passed: undefined

test failed: false
TLS Session ID
The TLS protocol is used by HTTPS to make connections secure. If the browser were to re-use a TLS session, then the session ID could be used to track users across websites.
              
Passed
write: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

read: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

result, same first party: 
95b263d86ea295cd66d656a86261f0729c8d5741ec1bbf359936d7be6e743030,
eb3ed4cd613dbafcc846741a1ff5688b49cc6c4fb883d902aa39cc3c5c344185,
e7a88667c599c1aa9e31fb3b52d3a686a77e46eb5494c1980f57913a707d5ea6,
f327dd2ba14c64993dce6d12f07a3fbe5535412ec3831a1c2a814c80423cbb48,
2132cc97f07200827c0c8ecf700b30799aba101fad8678891ed5a95e0ab8e9f6

result, different first party: 
718774f047a94c5976c76cdf24b0420d332db009f5f2799ab3b70e78ebe24ed3,
82a9cd9bd1d80e94db2f35026d32846dbebea9d553823cee497deb52bc7395ce,
0a9ebec0ead40e2b37d3148807d03c90f8147ed8d5f65d9676cd3e3c124e64a3,
950668a32554f2c3c31f63c82c341f76805b59a828cef3ddccfe171e7c8fc520,
92579a96c6055f32b9cbf8a3c7e9614d7c26687a042674c3d6ba46a720b70d45

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

read: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

result, same first party: 
9af127753295479357895ee3535565a20132eb6cb771f2df5e35dcc52720aada,
46316c8e4d325d649f2efa66127486e2534828f5202f57f361eb33986ea61cf8,
513982cf6944b9918ac5135589d93d573fd2dc4cff935a708509ae451bf2493b,
826c3852c16123b422ad0a803e067a3906e1982b64e7e3cfdcec4d554094d93b,
4f2bc9ded0df51269331dd3d3590d1cdc8d620242899b32a64472bfa9f975aee

result, different first party: 
80212fe5b5f3a562d9783f8ac87b39310020336681184c60417218c6fdc01c59,
52669e964f2dc9176106e7dea95c8cf8e507bc09cd391db8d684be76b2e6b8e5,
a9483afb23c2aa830514a6fc11bb740780f5c2c3b22609a0ad9b213429d4be75,
51356f3e7f3e395d0c2679a39c6e60d53a64e54a67be83ec164211bfd09c9d4d,
da545ea04b02b052c2e0bee1533816c677d3f7e6f59d8b28e2967eccd61a3bb3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

read: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

result, same first party: 
4d6d67460420682c3f8f9577348e347bcce98301c063bb9483c6ef59b28fd847,
c1f8d62b402acb7663ba091e480ea0a0c9c1614ddfe6d1bcade2d4b256798f67,
5a3dfa1a33bae6a73178b462938d1f7f66aff1e81de546b27ceec2f6f316ccec,
d3980d9755f798c70752505b93d9d73a811517f65301a8321d19c5baa4ca1c65,
fd9904ed2493ee783d6e2dcd1bb0b1c6a42671e9d3e60dac48c946ab7eb8a1e8

result, different first party: 
3b7e128b13a8608b78d03947504b0ba57ca5675b3a96094c46730f9b5e29b168,
d21775cdcb2b8d5679f33eea3db08423423d3b33a0188939b726cc99db4e6bc9,
0e33f81bef8008d3890397608ba39002b45cfbe06bd5a37a2d4ebab84e786ac9,
320fbfc3838a697c8d77c60a279d5101b34fa68df86a7e734a6e7a5b0dac9b8f,
ea196e0db0f4dfa43b1603f0a3e7b4feccf5c4f78589dd139d4a24a0c90b614e

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

read: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

result, same first party: 
ef09caf31763454212c0a620a49a9830b01af4008567d32e7f51d6c1e40c43ac,
9e28a99a04f4297265a2df114bc184170a61b28a3874621355b6fce270dec769,
03c5c5462f681ab6727898f3494e38541be8fdf39f69a2bfaabd157269780e67,
460d445d53bfa36a8c98aa3b8632b97cad1a7c237105c3b7952dedf045c25743,
877640ff2808bbb290c331357c4ea5c830812429a9e03ee0bb5cf97d69d7d512

result, different first party: 
a0887365a04d8a4699258a47c7a699ac819269e1d36a2410ce3b06b05d991809,
38e36aff75478466382998bae8871d210d5accf07100882df2e58a7d1b0a13b4,
ef592cbfad80ef9a3408f0438b7491818180b12073b40147a6acce2100647648,
d47843e78d72e003a20255a321bc465e8057e530810545925fa5b943e662cf19,
5c708e1bf598bcc1c47b760808414e30eca39dfbad513563cab77daeb182d2f2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

read: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

result, same first party: 
569fb5d9ba4290c74a7e44f826fb2a7f911f78f5fbe67d6efa41dacac5b9906e,
69684437c674f27ff11b4c6e5bfbec8804637f4e448fb26099d1eae24984f3df,
1b7eb18780622afb9bf04145120912135d603d65c23aa21d8d433ea90f57dd2b,
e3844c50f936c38f4f6579b1d06dbd9a52b0ab9a028311eb468f65c5d0f59dd8,
fdf2a340397a9e5993ba439390db2a39cb69a5e03fa96f2c0114edfd109d4bc4

result, different first party: 
2a9df1dd9379c77244fa8f544810120873703245d0ac3cf78e1c29f93871101e,
bfacb1a29c6ee233afd921b835df5e76d9f8134bffd618f12eae53496f3e9e7e,
961393df993aefcaeaf13ed753cd7e6f0e0caf38d74705b77a832229b4deb505,
bd82f59ee3dc0a1244823922e23fd69496f510d3660acbaed2c93d584099aa8a,
93b50e97503a78abd77b5f726f5cffe3fc5a877efd5533be3b8f5377987cb30b

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

read: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

result, same first party: 
b85e8c53e5eb5fdf869c457171373b431874b448c3e1505be32ec23031c67250,
17b56fccb74da69242ff076be9ce7a72f0a1f76c44090692d2a277b938da75fe,
5f8b0823b7cc7fdd903f194ecc01eb5044a67cdddd43d7a78055d39f4e6617fe,
7c474dec5be569009baadfbb47e4ddd2bb0f6ac5e2b13a111e8ed51f3a5af3dc,
aea938aa1c9fda141c5e8ce9bce2f368c5cd937df51477e1588bab0f5a1a4040

result, different first party: 
c49fc953e6187aa0b1480cdc9404d9426a78278dbf78ee0fa04c913e00286910,
9a313dcf834205471c067f5e280de9e9772dcae42a076942a1843837d9f3b068,
98e9d435355db853842a2dd9ff9db38228ebeab88f499816ae60c86694365367,
1c8de1216f791d380cb65d8fb31c36079a229cb20614db2f3d23cb4d3000d5ab,
a88d012162a629450ec1c6195af704c5bf0d98a437c556b943cd8c718f8c8a93

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

read: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

result, same first party: 
441d8548eb887d1cf4eb2e13bff48c5858c7ec9dc9b80855ed3f2f91ce08ff25,
48ba15045fea85a387e727e66f520ea845c224beefecbebbd72464994be58a8b,
a0190bebcf46b61985b0534a64243a6b84d9d1f02c79b41179a8f89221d6d719,
047404507ec42d34b3876fcd893168bd81c1871ca20671159c791ba00e340f76,
eb7357e3f21929345a0af5e3bda9d941b0fa0dc755007de12d6617db52c3e06f

result, different first party: 
a2fd9b242c4283ca8e0589ad12304e94d4a479ef1c84abc3f6233bbe3a715b9b,
610188a241a27ad858040ea1928c8b1998fb6d29d2abf6af7225b1d5076b5b68,
e01e253e10ae33ec2470b577843cd7fca20568e616fc367cf05de0e8edfc83f3,
98adcc7d5eac919c5696feaa7ba66ac89eaf59059f6c90ed661f9be663096dd8,
2428a61f7479df3f2ed2ef3e89a7d88e80edf29139083e384de738761d103ba0

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

read: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

result, same first party: 
6632556e3261f6037cb7f85466082a88018d004984ab8eef0c1ff8681f86ab77,
a3ecad8970dcb3652e0694e8106ac00f152d2251df2e6a7d02931b28d19d1339,
0b0a7915488d7006f4076d6dabd15e7a8277508faf077301415d0b35191ef628,
f810bd83dc608d2f57d2344e83882647ffbbc9148dfa5fe571b004c8210b29fa,
cdeba08266bc781edac678a3293b220f4d10cc653d651ebbd4180c4e92c3ad03

result, different first party: 
ce56b956224db2e882841b0e7a47a693c59b2c1b8cbb573a1ae98947332859ec,
1d16add08b21dd0971206f4276657a1c4d97a0c77799ba2a53ff30f4c207d4f0,
0c48c8e027c2ca237089e8834a5dee14f7b75374e564788b25deac3e804a59cd,
f061e6fa81bdc29a0b585d964ec522a9a935414081ef0701e9473882d570c368,
f27497f77107137176c00096fffbf93d73fc8f225d35b3c082563f91a77ead1a

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

read: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

result, same first party: 
526c426723e76c097a4a98fc8c6f7032aaf3467c4fbb878afff30858563ed145,
d1040e9890a95664a5b10450dfcf59a019a94d5102db97c1053abbdf501ee565,
ec65da4dbdc2324ea11291c20379a52f77dc7312e20bcbe8de167cca4ba5ac35,
e9186a574540e2332bbd823be3dfca3d2314bdeaca8b2f6cff044cbfbfabf8f3,
46a6b317cdef2dd946f9c96f12a40a1c28516070ac32d91296d1905c9bfe7037

result, different first party: 
85276879addd07065813a74e592646aec72bf5b2dcc5b1662a8bbb4ac81043a0,
f559281d4e2881f756f5a9fc29dc77275617e6bd168c98610a6753d43e0f3d74,
08a24d21c05716ce235e90ca1b14af545bbba70dc3f4888198b93bdfd4540374,
21313cf15cd28a544609ed76e088186569f5ea0e813b20594036ca197e50a606,
7576875b8de65e68c9c13faf1bd6fbd8af0d19a44306359b263ed9fa7201749e

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

read: async () => {
      let results = await fetch("https://tls.privacytests2.org:8900/");
      return (await results.json()).sessionId;
    }

result, same first party: 1aa4c1f5b554aac2c4e9b5344bb8230b22e0f2e6c2e8d4109ea478dcb6df178d

result, different first party: 8a74a0e4f4f5e4d3365277faa58e4e1d4259d55c252f31a0af559aabcf4ac0f5

unsupported: false

passed: true

test failed: false
XMLHttpRequest cache
Similar to the newer Fetch API, any resource received may be cached by the browser. The cache is potentially vulnerable to cross-site tracking attack.
              
Passed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 2, 2, 2, 2, 2

result, different first party: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 1, 1, 1, 1, 1

result, different first party: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same first party: 1

result, different first party: 2

unsupported: false

passed: true

test failed: false
Navigation testsWhich browsers prevent websites from sharing tracking data when you click on a link?
When you click a hyperlink to navigate your browser from one site to another, certain browser APIs allow the first site to communicate to the second site. These privacy vulnerabilities can be fixed by introducing new limits on how much data is transfered between sites.',
        
document.referrer
The Referer [sic] request header is a mechanism used by browsers to let a website know where the user is visiting from. This header is inherently tracking users across websites. In recent times, browsers have switched to a policy of trimming a referrer to convey less tracking information, but Referer continues to convey cross-site tracking data by default.
              
Failed
write: (secret) => { /* do nothing */ }

read: () => document.referrer

result, same first party: 
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/

result, different first party: 
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (secret) => { /* do nothing */ }

read: () => document.referrer

result, same first party: 
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/

result, different first party: 
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (secret) => { /* do nothing */ }

read: () => document.referrer

result, same first party: 
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/

result, different first party: 
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (secret) => { /* do nothing */ }

read: () => document.referrer

result, same first party: 
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/

result, different first party: 
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (secret) => { /* do nothing */ }

read: () => document.referrer

result, same first party: 
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/

result, different first party: 
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (secret) => { /* do nothing */ }

read: () => document.referrer

result, same first party: 
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/

result, different first party: 
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (secret) => { /* do nothing */ }

read: () => document.referrer

result, same first party: 
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/

result, different first party: 
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (secret) => { /* do nothing */ }

read: () => document.referrer

result, same first party: 
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (secret) => { /* do nothing */ }

read: () => document.referrer

result, same first party: 
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/

result, different first party: 
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/,
https://test-pages.privacytests2.org/

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (secret) => { /* do nothing */ }

read: () => document.referrer

result, same first party: https://test-pages.privacytests2.org/

result, different first party: https://test-pages.privacytests2.org/

unsupported: false

passed: false

test failed: false
sessionStorage
The sessionStorage API is similar to the localStorage API, but it does not persist across tabs or across browser sessions. Nonetheless, it can be used to track users if they navigate from one website to another. This tracking can be thwarted by partitioning sessionStorage between websites.
              
Passed
write: (secret) => sessionStorage.setItem("secret", secret)

read: () => sessionStorage.getItem("secret")

result, same first party: 
4bde1512-0784-43fb-887a-56a509216ec5,
41005147-8107-4a0f-bd00-5de04892fc40,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1,
bcde0d87-19c8-4d11-b69d-cf5b05adac32,
cf7b9801-6b0c-4efc-9361-c923491dbafc

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => sessionStorage.setItem("secret", secret)

read: () => sessionStorage.getItem("secret")

result, same first party: 
6ff0b878-e459-4077-873d-c4d73a8b4c3f,
94d0ff49-2e50-4f68-a576-2f481a9b0dfb,
db9ededa-3d85-49d1-b22f-66b9d13151e9,
eda356c0-dfbb-48c4-98bc-e3060f20796d,
45855e06-c12b-4c97-a80f-b05d0634705e

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => sessionStorage.setItem("secret", secret)

read: () => sessionStorage.getItem("secret")

result, same first party: 
58109673-6b30-4c3c-93dc-9f3935edeced,
2aa2bf6f-0a07-4a35-ae45-e9b6a1d11e20,
732a589c-ffa1-441f-b046-e96ae5ecce3b,
be322cbd-9046-492a-8283-325c7e6e36ca,
4d80e8ed-2942-4e43-80e6-7e11a7e16883

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => sessionStorage.setItem("secret", secret)

read: () => sessionStorage.getItem("secret")

result, same first party: 
9f1a20c0-3f9c-4aa5-8aa8-e56950e57e74,
e4fef07d-00dc-4960-8421-eaed44851eed,
154af211-304d-45c2-bd1d-edfcf6a953c2,
bbc94382-8354-43fa-9caa-06c72e77a772,
5cd2be12-be84-4ee2-ad4f-e8bd13d52186

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => sessionStorage.setItem("secret", secret)

read: () => sessionStorage.getItem("secret")

result, same first party: 
a09b69c9-0216-4504-9061-fc5c61dd3c23,
7b6315a4-06ef-4ac0-8f42-ce400041b707,
2d5c9ed0-3dbd-48e7-84ef-eb6e8484cdbf,
65902525-09ad-4c46-865a-d3fc1f63ac7b,
6e3bb471-c66f-4f24-8437-1dbee8645c0e

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => sessionStorage.setItem("secret", secret)

read: () => sessionStorage.getItem("secret")

result, same first party: 
c4e8c0f1-6882-4a88-b2b0-1abda72db45e,
ae52c0dc-9b2c-4efd-9348-d816b188d956,
9d44a7cf-1964-4a73-81b3-b7941a1a8e4d,
3a9a3eda-7e51-42b7-9ccf-5557bf5b9c77,
896b9c56-96e4-44cb-9a3b-76bd875cead7

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => sessionStorage.setItem("secret", secret)

read: () => sessionStorage.getItem("secret")

result, same first party: 
213faa81-9820-4e64-8ca2-4b2c56e0fd16,
cf7391f7-aa80-401f-81c4-7c2508844631,
6cb5025c-2699-446a-9372-39087b296a21,
9a0e433f-dc60-4ba4-ba79-fa1ff3caccb5,
4335c2dd-8867-446f-8184-bd81aa0654b6

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => sessionStorage.setItem("secret", secret)

read: () => sessionStorage.getItem("secret")

result, same first party: 
1e854cf6-6d0d-4987-b89f-4f0e6bfb3013,
2485a3ce-aa3e-4197-ba4a-2835da79e7ac,
f8e56e03-da27-4aae-9eee-18c4b864da6a,
63fc99e9-1362-4918-9b98-fd62c233cfaf,
7fe7e385-59f1-4ded-a894-f9710f27446e

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => sessionStorage.setItem("secret", secret)

read: () => sessionStorage.getItem("secret")

result, same first party: 
b4e6c154-78d4-4ea8-9de8-7342f2b90461,
a938646f-4e8a-409b-8a23-9aa66b47e388,
26e63861-906d-420b-bba7-f80b45898c34,
cda34f43-1255-481b-9e0d-1c216b86d6fa,
6779afe3-026e-4315-87e0-9c8f43f3c72c

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => sessionStorage.setItem("secret", secret)

read: () => sessionStorage.getItem("secret")

result, same first party: 40268717-416c-4353-9311-83b6625eb429

result, different first party: null

unsupported: false

passed: true

test failed: false
window.name
The window.name API allows websites to store data that will persist after the user has navigated the tab to a different website. This mechanism could be partitioned so that data is not allowed to persist between websites.
              
Passed
write: (secret) => window.name = "name_" + secret

read: () => window.name

result, same first party: 
name_4bde1512-0784-43fb-887a-56a509216ec5,
name_41005147-8107-4a0f-bd00-5de04892fc40,
name_f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1,
name_bcde0d87-19c8-4d11-b69d-cf5b05adac32,
name_cf7b9801-6b0c-4efc-9361-c923491dbafc

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => window.name = "name_" + secret

read: () => window.name

result, same first party: 
name_6ff0b878-e459-4077-873d-c4d73a8b4c3f,
name_94d0ff49-2e50-4f68-a576-2f481a9b0dfb,
name_db9ededa-3d85-49d1-b22f-66b9d13151e9,
name_eda356c0-dfbb-48c4-98bc-e3060f20796d,
name_45855e06-c12b-4c97-a80f-b05d0634705e

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => window.name = "name_" + secret

read: () => window.name

result, same first party: 
name_58109673-6b30-4c3c-93dc-9f3935edeced,
name_2aa2bf6f-0a07-4a35-ae45-e9b6a1d11e20,
name_732a589c-ffa1-441f-b046-e96ae5ecce3b,
name_be322cbd-9046-492a-8283-325c7e6e36ca,
name_4d80e8ed-2942-4e43-80e6-7e11a7e16883

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => window.name = "name_" + secret

read: () => window.name

result, same first party: 
name_9f1a20c0-3f9c-4aa5-8aa8-e56950e57e74,
name_e4fef07d-00dc-4960-8421-eaed44851eed,
name_154af211-304d-45c2-bd1d-edfcf6a953c2,
name_bbc94382-8354-43fa-9caa-06c72e77a772,
name_5cd2be12-be84-4ee2-ad4f-e8bd13d52186

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => window.name = "name_" + secret

read: () => window.name

result, same first party: 
name_a09b69c9-0216-4504-9061-fc5c61dd3c23,
name_7b6315a4-06ef-4ac0-8f42-ce400041b707,
name_2d5c9ed0-3dbd-48e7-84ef-eb6e8484cdbf,
name_65902525-09ad-4c46-865a-d3fc1f63ac7b,
name_6e3bb471-c66f-4f24-8437-1dbee8645c0e

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => window.name = "name_" + secret

read: () => window.name

result, same first party: 
name_c4e8c0f1-6882-4a88-b2b0-1abda72db45e,
name_ae52c0dc-9b2c-4efd-9348-d816b188d956,
name_9d44a7cf-1964-4a73-81b3-b7941a1a8e4d,
name_3a9a3eda-7e51-42b7-9ccf-5557bf5b9c77,
name_896b9c56-96e4-44cb-9a3b-76bd875cead7

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => window.name = "name_" + secret

read: () => window.name

result, same first party: 
name_213faa81-9820-4e64-8ca2-4b2c56e0fd16,
name_cf7391f7-aa80-401f-81c4-7c2508844631,
name_6cb5025c-2699-446a-9372-39087b296a21,
name_9a0e433f-dc60-4ba4-ba79-fa1ff3caccb5,
name_4335c2dd-8867-446f-8184-bd81aa0654b6

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => window.name = "name_" + secret

read: () => window.name

result, same first party: 
name_1e854cf6-6d0d-4987-b89f-4f0e6bfb3013,
name_2485a3ce-aa3e-4197-ba4a-2835da79e7ac,
name_f8e56e03-da27-4aae-9eee-18c4b864da6a,
name_63fc99e9-1362-4918-9b98-fd62c233cfaf,
name_7fe7e385-59f1-4ded-a894-f9710f27446e

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => window.name = "name_" + secret

read: () => window.name

result, same first party: 
name_b4e6c154-78d4-4ea8-9de8-7342f2b90461,
name_a938646f-4e8a-409b-8a23-9aa66b47e388,
name_26e63861-906d-420b-bba7-f80b45898c34,
name_cda34f43-1255-481b-9e0d-1c216b86d6fa,
name_6779afe3-026e-4315-87e0-9c8f43f3c72c

result, different first party: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => window.name = "name_" + secret

read: () => window.name

result, same first party: name_40268717-416c-4353-9311-83b6625eb429

result, different first party: 

unsupported: false

passed: true

test failed: false
HTTPS testsWhich browsers prevent unencrypted network connections?
HTTPS is the protocol that web browsers use to connect securely to websites. When HTTPS is being used, the connection is encrypted so that third parties on the network cannot read content being sent between the server and your browser. In the past, insecure connections were the default and websites would need to actively request that a browser use HTTPS. Now the status quo is shifting, and browser makers are moving toward a world where HTTPS is the default protocol.`
        
Insecure website warning
Checks to see if the browser stops loading an insecure website and warns the user before giving them the option to continue. Known as HTTPS-Only Mode in some browsers.
              
Failed
passed: false, false, false, false, false
result: 
Insecure website loaded,
Insecure website loaded,
Insecure website loaded,
Insecure website loaded,
Insecure website loaded
Failed
passed: false, false, false, false, false
result: 
Insecure website loaded,
Insecure website loaded,
Insecure website loaded,
Insecure website loaded,
Insecure website loaded
Failed
passed: false, false, false, false, false
result: 
Insecure website loaded,
Insecure website loaded,
Insecure website loaded,
Insecure website loaded,
Insecure website loaded
Failed
passed: false, false, false, false, false
result: 
Insecure website loaded,
Insecure website loaded,
Insecure website loaded,
Insecure website loaded,
Insecure website loaded
Failed
passed: false, false, false, false, false
result: 
Insecure website loaded,
Insecure website loaded,
Insecure website loaded,
Insecure website loaded,
Insecure website loaded
Failed
passed: false, false, false, false, false
result: 
Insecure website loaded,
Insecure website loaded,
Insecure website loaded,
Insecure website loaded,
Insecure website loaded
Failed
passed: false, false, false, false, false
result: 
Insecure website loaded,
Insecure website loaded,
Insecure website loaded,
Insecure website loaded,
Insecure website loaded
Failed
passed: false, false, false, false, false
result: 
Insecure website loaded,
Insecure website loaded,
Insecure website loaded,
Insecure website loaded,
Insecure website loaded
Failed
passed: false, false, false, false, false
result: 
Insecure website loaded,
Insecure website loaded,
Insecure website loaded,
Insecure website loaded,
Insecure website loaded
Failed
passed: false
result: Insecure website loaded
Upgradable address
Checks to see if an insecure address entered into the browser's address bar is upgraded to HTTPS whenever possible.
              
Failed
upgraded: false, false, false, false, false
passed: false, false, false, false, false
Failed
upgraded: false, false, false, false, false
passed: false, false, false, false, false
Failed
upgraded: false, false, false, false, false
passed: false, false, false, false, false
Failed
upgraded: false, false, false, false, false
passed: false, false, false, false, false
Failed
upgraded: false, false, false, false, false
passed: false, false, false, false, false
Failed
upgraded: false, false, false, false, false
passed: false, false, false, false, false
Failed
upgraded: false, false, false, false, false
passed: false, false, false, false, false
Failed
upgraded: false, false, false, false, false
passed: false, false, false, false, false
Failed
upgraded: false, false, false, false, false
passed: false, false, false, false, false
Failed
upgraded: false
passed: false
Upgradable hyperlink
Checks to see if the user has clicked on a hyperlink to an insecure address, if the browser upgrades that address to HTTPS whenever possible.
              
Failed
upgraded: false, false, false, false, false
passed: false, false, false, false, false
Failed
upgraded: false, false, false, false, false
passed: false, false, false, false, false
Failed
upgraded: false, false, false, false, false
passed: false, false, false, false, false
Failed
upgraded: false, false, false, false, false
passed: false, false, false, false, false
Failed
upgraded: false, false, false, false, false
passed: false, false, false, false, false
Failed
upgraded: false, false, false, false, false
passed: false, false, false, false, false
Failed
upgraded: false, false, false, false, false
passed: false, false, false, false, false
Failed
upgraded: false, false, false, false, false
passed: false, false, false, false, false
Failed
upgraded: false, false, false, false, false
passed: false, false, false, false, false
Failed
upgraded: false
passed: false
Upgradable image
Checks to see if the browser attempts to upgrade an insecure address for an image to HTTPS whenever possible.
              
Passed
passed: true, true, true, true, true
result: upgraded, upgraded, upgraded, upgraded, upgraded
Passed
passed: true, true, true, true, true
result: upgraded, upgraded, upgraded, upgraded, upgraded
Failed
passed: false, false, false, false, false
result: 
loaded insecurely,
loaded insecurely,
loaded insecurely,
loaded insecurely,
loaded insecurely
Passed
passed: true, true, true, true, true
result: upgraded, upgraded, upgraded, upgraded, upgraded
Failed
passed: false, false, false, false, false
result: 
loaded insecurely,
loaded insecurely,
loaded insecurely,
loaded insecurely,
loaded insecurely
Failed
passed: false, false, false, false, false
result: 
loaded insecurely,
loaded insecurely,
loaded insecurely,
loaded insecurely,
loaded insecurely
Failed
passed: false, false, false, false, false
result: 
loaded insecurely,
loaded insecurely,
loaded insecurely,
loaded insecurely,
loaded insecurely
Failed
passed: false, false, false, false, false
result: 
loaded insecurely,
loaded insecurely,
loaded insecurely,
loaded insecurely,
loaded insecurely
Passed
passed: true, true, true, true, true
result: upgraded, upgraded, upgraded, upgraded, upgraded
Failed
passed: false
result: loaded insecurely
Upgradable script
Checks to see if the browser attempts to upgrade an insecure address for an script to HTTPS whenever possible.
              
Passed
passed: true, true, true, true, true
result: blocked, blocked, blocked, blocked, blocked
Passed
passed: true, true, true, true, true
result: blocked, blocked, blocked, blocked, blocked
Passed
passed: true, true, true, true, true
result: blocked, blocked, blocked, blocked, blocked
Passed
passed: true, true, true, true, true
result: blocked, blocked, blocked, blocked, blocked
Passed
passed: true, true, true, true, true
result: blocked, blocked, blocked, blocked, blocked
Passed
passed: true, true, true, true, true
result: blocked, blocked, blocked, blocked, blocked
Passed
passed: true, true, true, true, true
result: blocked, blocked, blocked, blocked, blocked
Passed
passed: true, true, true, true, true
result: blocked, blocked, blocked, blocked, blocked
Passed
passed: true, true, true, true, true
result: blocked, blocked, blocked, blocked, blocked
Passed
passed: true
result: blocked
Misc testsWhich browsers provide additional assorted privacy protections?
This category includes tests for the presence of miscellaneous privacy features
        
ECH enabled
Encrypted Client Hello (ECH) is a new protocol that hides the website you are visiting from third-party network eavesdroppers.
              
Failed
SNI_status: plaintext
passed: false, false, false, false, false
Failed
SNI_status: plaintext
passed: false, false, false, false, false
Failed
SNI_status: plaintext
passed: false, false, false, false, false
Failed
SNI_status: plaintext
passed: false, false, false, false, false
Failed
SNI_status: plaintext
passed: false, false, false, false, false
Failed
SNI_status: plaintext
passed: false, false, false, false, false
Failed
SNI_status: plaintext
passed: false, false, false, false, false
Failed
SNI_status: plaintext
passed: false, false, false, false, false
Failed
SNI_status: plaintext
passed: false, false, false, false, false
Failed
SNI_status: plaintext
passed: false
GPC enabled first-party
The Global Privacy Control is an HTTP header that can be sent by a browser to instruct a website not to sell the user's personal data to third parties. This test checks to see if the GPC header is sent by default to the top-level website.
              
Failed
header value: undefined
passed: false, false, false, false, false
Failed
header value: undefined
passed: false, false, false, false, false
Failed
header value: undefined
passed: false, false, false, false, false
Failed
header value: undefined
passed: false, false, false, false, false
Failed
header value: undefined
passed: false, false, false, false, false
Failed
header value: undefined
passed: false, false, false, false, false
Failed
header value: undefined
passed: false, false, false, false, false
Failed
header value: undefined
passed: false, false, false, false, false
Failed
header value: undefined
passed: false, false, false, false, false
Failed
header value: undefined
passed: false
GPC enabled third-party
The Global Privacy Control is an HTTP header that can be sent by a browser to instruct a visited website not to sell the user's personal data to other parties. This test checks to see if the GPC header is sent to third-party elements on the web page.
              
Failed
passed: false, false, false, false, false
Failed
passed: false, false, false, false, false
Failed
passed: false, false, false, false, false
Failed
passed: false, false, false, false, false
Failed
passed: false, false, false, false, false
Failed
passed: false, false, false, false, false
Failed
passed: false, false, false, false, false
Failed
passed: false, false, false, false, false
Failed
passed: false, false, false, false, false
Failed
passed: false
IP address leak
IP addresses can be used to uniquely identify a large percentage of users. A proxy, VPN, or Tor can mask a user's IP address.
              
Failed
passed: false, false, false, false, false
Failed
passed: false, false, false, false, false
Failed
passed: false, false, false, false, false
Failed
passed: false, false, false, false, false
Failed
passed: false, false, false, false, false
Failed
passed: false, false, false, false, false
Failed
passed: false, false, false, false, false
Failed
passed: false, false, false, false, false
Failed
passed: false, false, false, false, false
Failed
passed: false
Stream isolation
Browsers that use Tor can use a different Tor circuit per top-level website.
              
Unsupported
write: () => {
      if (!usingTor) {
        throw new Error("Unsupported");
      }
    }
read: async () => {
      if (usingTor) {
        return ipAddress;
      } else {
        throw new Error("Unsupported");
      }
    }
unsupported: true, true, true, true, true
readSameFirstParty: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported
readDifferentFirstParty: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported
testFailed: false, false, false, false, false
Unsupported
write: () => {
      if (!usingTor) {
        throw new Error("Unsupported");
      }
    }
read: async () => {
      if (usingTor) {
        return ipAddress;
      } else {
        throw new Error("Unsupported");
      }
    }
unsupported: true, true, true, true, true
readSameFirstParty: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported
readDifferentFirstParty: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported
testFailed: false, false, false, false, false
Unsupported
write: () => {
      if (!usingTor) {
        throw new Error("Unsupported");
      }
    }
read: async () => {
      if (usingTor) {
        return ipAddress;
      } else {
        throw new Error("Unsupported");
      }
    }
unsupported: true, true, true, true, true
readSameFirstParty: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported
readDifferentFirstParty: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported
testFailed: false, false, false, false, false
Unsupported
write: () => {
      if (!usingTor) {
        throw new Error("Unsupported");
      }
    }
read: async () => {
      if (usingTor) {
        return ipAddress;
      } else {
        throw new Error("Unsupported");
      }
    }
unsupported: true, true, true, true, true
readSameFirstParty: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported
readDifferentFirstParty: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported
testFailed: false, false, false, false, false
Unsupported
write: () => {
      if (!usingTor) {
        throw new Error("Unsupported");
      }
    }
read: async () => {
      if (usingTor) {
        return ipAddress;
      } else {
        throw new Error("Unsupported");
      }
    }
unsupported: true, true, true, true, true
readSameFirstParty: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported
readDifferentFirstParty: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported
testFailed: false, false, false, false, false
Unsupported
write: () => {
      if (!usingTor) {
        throw new Error("Unsupported");
      }
    }
read: async () => {
      if (usingTor) {
        return ipAddress;
      } else {
        throw new Error("Unsupported");
      }
    }
unsupported: true, true, true, true, true
readSameFirstParty: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported
readDifferentFirstParty: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported
testFailed: false, false, false, false, false
Unsupported
write: () => {
      if (!usingTor) {
        throw new Error("Unsupported");
      }
    }
read: async () => {
      if (usingTor) {
        return ipAddress;
      } else {
        throw new Error("Unsupported");
      }
    }
unsupported: true, true, true, true, true
readSameFirstParty: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported
readDifferentFirstParty: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported
testFailed: false, false, false, false, false
Unsupported
write: () => {
      if (!usingTor) {
        throw new Error("Unsupported");
      }
    }
read: async () => {
      if (usingTor) {
        return ipAddress;
      } else {
        throw new Error("Unsupported");
      }
    }
unsupported: true, true, true, true, true
readSameFirstParty: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported
readDifferentFirstParty: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported
testFailed: false, false, false, false, false
Unsupported
write: () => {
      if (!usingTor) {
        throw new Error("Unsupported");
      }
    }
read: async () => {
      if (usingTor) {
        return ipAddress;
      } else {
        throw new Error("Unsupported");
      }
    }
unsupported: true, true, true, true, true
readSameFirstParty: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported
readDifferentFirstParty: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported
testFailed: false, false, false, false, false
Unsupported
write: () => {
      if (!usingTor) {
        throw new Error("Unsupported");
      }
    }
read: async () => {
      if (usingTor) {
        return ipAddress;
      } else {
        throw new Error("Unsupported");
      }
    }
unsupported: true
readSameFirstParty: Error: Unsupported
readDifferentFirstParty: Error: Unsupported
testFailed: false
Tor enabled
The Tor network sends the browser's web requests through a series of relays to hide a user's IP address, thereby helping to mask their identity and location. This test checks to see if the Tor network is being used by default.
              
Failed
IsTorExit: false, false, false, false, false
passed: false, false, false, false, false
Failed
IsTorExit: false, false, false, false, false
passed: false, false, false, false, false
Failed
IsTorExit: false, false, false, false, false
passed: false, false, false, false, false
Failed
IsTorExit: false, false, false, false, false
passed: false, false, false, false, false
Failed
IsTorExit: false, false, false, false, false
passed: false, false, false, false, false
Failed
IsTorExit: false, false, false, false, false
passed: false, false, false, false, false
Failed
IsTorExit: false, false, false, false, false
passed: false, false, false, false, false
Failed
IsTorExit: false, false, false, false, false
passed: false, false, false, false, false
Failed
IsTorExit: false, false, false, false, false
passed: false, false, false, false, false
Failed
IsTorExit: false
passed: false
Fingerprinting resistance testsWhich browsers hide what's unique about your device?
Fingerprinting is a technique trackers use to uniquely identify you as you browse the web. A fingerprinting script will measure several characteristics of your browser and, combining this data, will build a fingerprint that may uniquely identify you among web users. Browsers can introduce countermeasures, such as minimizing the distinguishing information disclosed by certain web APIs so your browser is harder to pick out from the crowd (so-called 'fingerprinting resistance').`,
        
Media query screen height
Height of the user's screen in pixels.
              
Failed
expression: undefined
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: undefined
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: undefined
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: undefined
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: undefined
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: undefined
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: undefined
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: undefined
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: undefined
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: undefined
desired expression: undefined
actual value: 667
desired value: undefined
passed: false
Media query screen width
Width of the user's screen in pixels.
              
Failed
expression: undefined
desired expression: undefined
actual value: 375,375,375,375,375
desired value: undefined
passed: false,false,false,false,false
Failed
expression: undefined
desired expression: undefined
actual value: 375,375,375,375,375
desired value: undefined
passed: false,false,false,false,false
Failed
expression: undefined
desired expression: undefined
actual value: 375,375,375,375,375
desired value: undefined
passed: false,false,false,false,false
Failed
expression: undefined
desired expression: undefined
actual value: 375,375,375,375,375
desired value: undefined
passed: false,false,false,false,false
Failed
expression: undefined
desired expression: undefined
actual value: 375,375,375,375,375
desired value: undefined
passed: false,false,false,false,false
Failed
expression: undefined
desired expression: undefined
actual value: 375,375,375,375,375
desired value: undefined
passed: false,false,false,false,false
Failed
expression: undefined
desired expression: undefined
actual value: 375,375,375,375,375
desired value: undefined
passed: false,false,false,false,false
Failed
expression: undefined
desired expression: undefined
actual value: 375,375,375,375,375
desired value: undefined
passed: false,false,false,false,false
Failed
expression: undefined
desired expression: undefined
actual value: 375,375,375,375,375
desired value: undefined
passed: false,false,false,false,false
Failed
expression: undefined
desired expression: undefined
actual value: 375
desired value: undefined
passed: false
outerHeight
Height of the browser window in pixels, including browser chrome.
              
Failed
expression: outerHeight
desired expression: undefined
actual value: 543,543,543,543,543
desired value: undefined
passed: false,false,false,false,false
Failed
expression: outerHeight
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: outerHeight
desired expression: undefined
actual value: 546,546,546,546,546
desired value: undefined
passed: false,false,false,false,false
Failed
expression: outerHeight
desired expression: undefined
actual value: 561,561,561,561,561
desired value: undefined
passed: false,false,false,false,false
Failed
expression: outerHeight
desired expression: undefined
actual value: 526,526,526,526,526
desired value: undefined
passed: false,false,false,false,false
Failed
expression: outerHeight
desired expression: undefined
actual value: 547,547,547,547,547
desired value: undefined
passed: false,false,false,false,false
Failed
expression: outerHeight
desired expression: undefined
actual value: 555,555,555,555,555
desired value: undefined
passed: false,false,false,false,false
Passed
expression: outerHeight
desired expression: undefined
actual value: 1428,1428,1428,1428,1428
desired value: undefined
passed: true,true,true,true,true
Failed
expression: outerHeight
desired expression: undefined
actual value: 508,508,508,508,508
desired value: undefined
passed: false,false,false,false,false
Failed
expression: outerHeight
desired expression: undefined
actual value: 667
desired value: undefined
passed: false
screen.height
Height of the user's screen, in pixels.
              
Failed
expression: screen.height
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: screen.height
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: screen.height
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: screen.height
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: screen.height
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: screen.height
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: screen.height
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: screen.height
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: screen.height
desired expression: undefined
actual value: 667,667,667,667,667
desired value: undefined
passed: false,false,false,false,false
Failed
expression: screen.height
desired expression: undefined
actual value: 667
desired value: undefined
passed: false
screen.width
Width of the user's screen, in pixels.
              
Failed
expression: screen.width
desired expression: undefined
actual value: 375,375,375,375,375
desired value: undefined
passed: false,false,false,false,false
Failed
expression: screen.width
desired expression: undefined
actual value: 375,375,375,375,375
desired value: undefined
passed: false,false,false,false,false
Failed
expression: screen.width
desired expression: undefined
actual value: 375,375,375,375,375
desired value: undefined
passed: false,false,false,false,false
Failed
expression: screen.width
desired expression: undefined
actual value: 375,375,375,375,375
desired value: undefined
passed: false,false,false,false,false
Failed
expression: screen.width
desired expression: undefined
actual value: 375,375,375,375,375
desired value: undefined
passed: false,false,false,false,false
Failed
expression: screen.width
desired expression: undefined
actual value: 375,375,375,375,375
desired value: undefined
passed: false,false,false,false,false
Failed
expression: screen.width
desired expression: undefined
actual value: 375,375,375,375,375
desired value: undefined
passed: false,false,false,false,false
Failed
expression: screen.width
desired expression: undefined
actual value: 375,375,375,375,375
desired value: undefined
passed: false,false,false,false,false
Failed
expression: screen.width
desired expression: undefined
actual value: 375,375,375,375,375
desired value: undefined
passed: false,false,false,false,false
Failed
expression: screen.width
desired expression: undefined
actual value: 375
desired value: undefined
passed: false
screenX
Position, in pixels, of the left edge of the browser window on screen.
              
Passed
expression: screenX
desired expression: undefined
actual value: 0,0,0,0,0
desired value: undefined
passed: true,true,true,true,true
Passed
expression: screenX
desired expression: undefined
actual value: 0,0,0,0,0
desired value: undefined
passed: true,true,true,true,true
Passed
expression: screenX
desired expression: undefined
actual value: 0,0,0,0,0
desired value: undefined
passed: true,true,true,true,true
Passed
expression: screenX
desired expression: undefined
actual value: 0,0,0,0,0
desired value: undefined
passed: true,true,true,true,true
Passed
expression: screenX
desired expression: undefined
actual value: 0,0,0,0,0
desired value: undefined
passed: true,true,true,true,true
Passed
expression: screenX
desired expression: undefined
actual value: 0,0,0,0,0
desired value: undefined
passed: true,true,true,true,true
Passed
expression: screenX
desired expression: undefined
actual value: 0,0,0,0,0
desired value: undefined
passed: true,true,true,true,true
Passed
expression: screenX
desired expression: undefined
actual value: 0,0,0,0,0
desired value: undefined
passed: true,true,true,true,true
Passed
expression: screenX
desired expression: undefined
actual value: 0,0,0,0,0
desired value: undefined
passed: true,true,true,true,true
Passed
expression: screenX
desired expression: undefined
actual value: 0
desired value: undefined
passed: true
screenY
Position, in pixels, of the top edge of the browser window on screen.
              
Passed
expression: screenY
desired expression: undefined
actual value: 0,0,0,0,0
desired value: undefined
passed: true,true,true,true,true
Passed
expression: screenY
desired expression: undefined
actual value: 0,0,0,0,0
desired value: undefined
passed: true,true,true,true,true
Passed
expression: screenY
desired expression: undefined
actual value: 0,0,0,0,0
desired value: undefined
passed: true,true,true,true,true
Passed
expression: screenY
desired expression: undefined
actual value: 0,0,0,0,0
desired value: undefined
passed: true,true,true,true,true
Passed
expression: screenY
desired expression: undefined
actual value: 0,0,0,0,0
desired value: undefined
passed: true,true,true,true,true
Passed
expression: screenY
desired expression: undefined
actual value: 0,0,0,0,0
desired value: undefined
passed: true,true,true,true,true
Passed
expression: screenY
desired expression: undefined
actual value: 0,0,0,0,0
desired value: undefined
passed: true,true,true,true,true
Passed
expression: screenY
desired expression: undefined
actual value: 0,0,0,0,0
desired value: undefined
passed: true,true,true,true,true
Passed
expression: screenY
desired expression: undefined
actual value: 0,0,0,0,0
desired value: undefined
passed: true,true,true,true,true
Passed
expression: screenY
desired expression: undefined
actual value: 0
desired value: undefined
passed: true
Tracking query parameter testsWhich browsers remove URL parameters that can track you?
When you browse from one web page to another, tracking companies will frequently attach a 'tracking query parameter' to the address of the second web page. That query parameter may contain a unique identifier that tracks you individually as you browse the web. And these query parameters are frequently synchronized with cookies, making them a powerful tracking vector. Web browsers can protect you from known tracking query parameters by stripping them from web addresses before your browser sends them. (The set of tracking query parameters tested here was largely borrowed from Brave.)`
        
__hsfp
HubSpot tracking parameter
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
__hssc
HubSpot tracking parameter
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
__hstc
HubSpot tracking parameter
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
__s
Drip.com email address tracking parameter
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
_hsenc
HubSpot tracking parameter
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
_openstat
Yandex tracking parameter
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
dclid
DoubleClick Click ID (Google)
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
fbclid
Facebook Click Identifier
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
gclid
Google Click Identifier
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
hsCtaTracking
HubSpot tracking parameter
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
mc_eid
Mailchimp Email ID (email recipient's address)
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
mkt_tok
Adobe Marketo tracking parameter
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
ml_subscriber
MailerLite email tracking
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
ml_subscriber_hash
MailerLite email tracking
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
msclkid
Microsoft Click ID
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
oly_anon_id
Omeda marketing 'anonymous' customer id
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
oly_enc_id
Omeda marketing 'known' customer id
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
rb_clickid
Unknown high-entropy tracking parameter
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
s_cid
Adobe Site Catalyst tracking parameter
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
vero_conv
Vero tracking parameter
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
vero_id
Vero tracking parameter
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
wickedid
Wicked Reports e-commerce tracking
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
yclid
Yandex Click ID
              
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false, false, false, false, false
Passed
passed: true, true, true, true, true
Failed
value: 3928911665442163
passed: false, false, false, false, false
Failed
value: 3928911665442163
passed: false
Tracker content blocking testsWhich browsers block important known tracking scripts and pixels?
When you visit a web page, it frequently has third-party embedded tracking content, such as scripts and tracking pixels. These embedded components spy on you. Some browsers and browser extensions maintain list of tracking companies and block their content from being loaded. This section checks to see if a browser blocks 20 of the largest trackers listed by https://whotracks.me.`
        
Adobe
Tests whether the browser blocks the page from loading the tracker at https://munchkin.marketo.net/munchkin.js
              
Passed
url: https://munchkin.marketo.net/munchkin.js
passed: true, true, true, true, true
Failed
url: https://munchkin.marketo.net/munchkin.js
passed: false, false, false, false, false
Passed
url: https://munchkin.marketo.net/munchkin.js
passed: true, true, true, true, true
Failed
url: https://munchkin.marketo.net/munchkin.js
passed: false, false, false, false, false
Failed
url: https://munchkin.marketo.net/munchkin.js
passed: false, false, false, false, false
Passed
url: https://munchkin.marketo.net/munchkin.js
passed: true, true, true, true, true
Failed
url: https://munchkin.marketo.net/munchkin.js
passed: false, false, false, false, false
Failed
url: https://munchkin.marketo.net/munchkin.js
passed: false, false, false, false, false
Failed
url: https://munchkin.marketo.net/munchkin.js
passed: false, false, false, false, false
Failed
url: https://munchkin.marketo.net/munchkin.js
passed: false
Adobe Audience Manager
Tests whether the browser blocks the page from loading the tracker at https://dpm.demdex.net/ibs
              
Passed
url: https://dpm.demdex.net/ibs
passed: true, true, true, true, true
Failed
url: https://dpm.demdex.net/ibs
passed: false, false, false, false, false
Passed
url: https://dpm.demdex.net/ibs
passed: true, true, true, true, true
Failed
url: https://dpm.demdex.net/ibs
passed: false, false, false, false, false
Failed
url: https://dpm.demdex.net/ibs
passed: false, false, false, false, false
Passed
url: https://dpm.demdex.net/ibs
passed: true, true, true, true, true
Failed
url: https://dpm.demdex.net/ibs
passed: false, false, false, false, false
Failed
url: https://dpm.demdex.net/ibs
passed: false, false, false, false, false
Failed
url: https://dpm.demdex.net/ibs
passed: false, false, false, false, false
Failed
url: https://dpm.demdex.net/ibs
passed: false
Amazon adsystem
Tests whether the browser blocks the page from loading the tracker at https://s.amazon-adsystem.com/dcm
              
Passed
url: https://s.amazon-adsystem.com/dcm
passed: true, true, true, true, true
Failed
url: https://s.amazon-adsystem.com/dcm
passed: false, false, false, false, false
Passed
url: https://s.amazon-adsystem.com/dcm
passed: true, true, true, true, true
Failed
url: https://s.amazon-adsystem.com/dcm
passed: false, false, false, false, false
Failed
url: https://s.amazon-adsystem.com/dcm
passed: false, false, false, false, false
Passed
url: https://s.amazon-adsystem.com/dcm
passed: true, true, true, true, true
Passed
url: https://s.amazon-adsystem.com/dcm
passed: true, true, true, true, true
Failed
url: https://s.amazon-adsystem.com/dcm
passed: false, false, false, false, false
Failed
url: https://s.amazon-adsystem.com/dcm
passed: false, false, false, false, false
Failed
url: https://s.amazon-adsystem.com/dcm
passed: false
AppNexus
Tests whether the browser blocks the page from loading the tracker at https://ib.adnxs.com/px?id=178248&t=1
              
Passed
url: https://ib.adnxs.com/px?id=178248&t=1
passed: true, true, true, true, true
Failed
url: https://ib.adnxs.com/px?id=178248&t=1
passed: false, false, false, false, false
Passed
url: https://ib.adnxs.com/px?id=178248&t=1
passed: true, true, true, true, true
Failed
url: https://ib.adnxs.com/px?id=178248&t=1
passed: false, false, false, false, false
Failed
url: https://ib.adnxs.com/px?id=178248&t=1
passed: false, false, false, false, false
Passed
url: https://ib.adnxs.com/px?id=178248&t=1
passed: true, true, true, true, true
Passed
url: https://ib.adnxs.com/px?id=178248&t=1
passed: true, true, true, true, true
Failed
url: https://ib.adnxs.com/px?id=178248&t=1
passed: false, false, false, false, false
Failed
url: https://ib.adnxs.com/px?id=178248&t=1
passed: false, false, false, false, false
Failed
url: https://ib.adnxs.com/px?id=178248&t=1
passed: false
Bing Ads
Tests whether the browser blocks the page from loading the tracker at https://bat.bing.com/bat.js
              
Passed
url: https://bat.bing.com/bat.js
passed: true, true, true, true, true
Failed
url: https://bat.bing.com/bat.js
passed: false, false, false, false, false
Passed
url: https://bat.bing.com/bat.js
passed: true, true, true, true, true
Failed
url: https://bat.bing.com/bat.js
passed: false, false, false, false, false
Failed
url: https://bat.bing.com/bat.js
passed: false, false, false, false, false
Failed
url: https://bat.bing.com/bat.js
passed: false, false, false, false, false
Failed
url: https://bat.bing.com/bat.js
passed: false, false, false, false, false
Failed
url: https://bat.bing.com/bat.js
passed: false, false, false, false, false
Failed
url: https://bat.bing.com/bat.js
passed: false, false, false, false, false
Failed
url: https://bat.bing.com/bat.js
passed: false
Chartbeat
Tests whether the browser blocks the page from loading the tracker at https://static.chartbeat.com/js/chartbeat.js
              
Passed
url: https://static.chartbeat.com/js/chartbeat.js
passed: true, true, true, true, true
Failed
url: https://static.chartbeat.com/js/chartbeat.js
passed: false, false, false, false, false
Passed
url: https://static.chartbeat.com/js/chartbeat.js
passed: true, true, true, true, true
Failed
url: https://static.chartbeat.com/js/chartbeat.js
passed: false, false, false, false, false
Failed
url: https://static.chartbeat.com/js/chartbeat.js
passed: false, false, false, false, false
Passed
url: https://static.chartbeat.com/js/chartbeat.js
passed: true, true, true, true, true
Failed
url: https://static.chartbeat.com/js/chartbeat.js
passed: false, false, false, false, false
Passed
url: https://static.chartbeat.com/js/chartbeat.js
passed: true, true, true, true, true
Failed
url: https://static.chartbeat.com/js/chartbeat.js
passed: false, false, false, false, false
Failed
url: https://static.chartbeat.com/js/chartbeat.js
passed: false
Criteo
Tests whether the browser blocks the page from loading the tracker at https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx
              
Passed
url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx
passed: true, true, true, true, true
Failed
url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx
passed: false, false, false, false, false
Passed
url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx
passed: true, true, true, true, true
Failed
url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx
passed: false, false, false, false, false
Failed
url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx
passed: false, false, false, false, false
Passed
url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx
passed: true, true, true, true, true
Failed
url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx
passed: false, false, false, false, false
Failed
url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx
passed: false, false, false, false, false
Failed
url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx
passed: false, false, false, false, false
Failed
url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx
passed: false
DoubleClick (Google)
Tests whether the browser blocks the page from loading the tracker at https://securepubads.g.doubleclick.net/static/glade.js
              
Passed
url: https://securepubads.g.doubleclick.net/static/glade.js
passed: true, true, true, true, true
Failed
url: https://securepubads.g.doubleclick.net/static/glade.js
passed: false, false, false, false, false
Passed
url: https://securepubads.g.doubleclick.net/static/glade.js
passed: true, true, true, true, true
Failed
url: https://securepubads.g.doubleclick.net/static/glade.js
passed: false, false, false, false, false
Failed
url: https://securepubads.g.doubleclick.net/static/glade.js
passed: false, false, false, false, false
Passed
url: https://securepubads.g.doubleclick.net/static/glade.js
passed: true, true, true, true, true
Passed
url: https://securepubads.g.doubleclick.net/static/glade.js
passed: true, true, true, true, true
Failed
url: https://securepubads.g.doubleclick.net/static/glade.js
passed: false, false, false, false, false
Failed
url: https://securepubads.g.doubleclick.net/static/glade.js
passed: false, false, false, false, false
Failed
url: https://securepubads.g.doubleclick.net/static/glade.js
passed: false
Facebook tracking
Tests whether the browser blocks the page from loading the tracker at https://connect.facebook.net/en_US/fbevents.js
              
Passed
url: https://connect.facebook.net/en_US/fbevents.js
passed: true, true, true, true, true
Failed
url: https://connect.facebook.net/en_US/fbevents.js
passed: false, false, false, false, false
Passed
url: https://connect.facebook.net/en_US/fbevents.js
passed: true, true, true, true, true
Failed
url: https://connect.facebook.net/en_US/fbevents.js
passed: false, false, false, false, false
Failed
url: https://connect.facebook.net/en_US/fbevents.js
passed: false, false, false, false, false
Passed
url: https://connect.facebook.net/en_US/fbevents.js
passed: true, true, true, true, true
Failed
url: https://connect.facebook.net/en_US/fbevents.js
passed: false, false, false, false, false
Passed
url: https://connect.facebook.net/en_US/fbevents.js
passed: true, true, true, true, true
Failed
url: https://connect.facebook.net/en_US/fbevents.js
passed: false, false, false, false, false
Failed
url: https://connect.facebook.net/en_US/fbevents.js
passed: false
Google (third-party ad pixel)
Tests whether the browser blocks the page from loading the tracker at https://www.google.com/pagead/1p-user-list/
              
Passed
url: https://www.google.com/pagead/1p-user-list/
passed: true, true, true, true, true
Failed
url: https://www.google.com/pagead/1p-user-list/
passed: false, false, false, false, false
Passed
url: https://www.google.com/pagead/1p-user-list/
passed: true, true, true, true, true
Failed
url: https://www.google.com/pagead/1p-user-list/
passed: false, false, false, false, false
Failed
url: https://www.google.com/pagead/1p-user-list/
passed: false, false, false, false, false
Failed
url: https://www.google.com/pagead/1p-user-list/
passed: false, false, false, false, false
Passed
url: https://www.google.com/pagead/1p-user-list/
passed: true, true, true, true, true
Failed
url: https://www.google.com/pagead/1p-user-list/
passed: false, false, false, false, false
Failed
url: https://www.google.com/pagead/1p-user-list/
passed: false, false, false, false, false
Failed
url: https://www.google.com/pagead/1p-user-list/
passed: false
Google Analytics
Tests whether the browser blocks the page from loading the tracker at https://google-analytics.com/urchin.js
              
Passed
url: https://google-analytics.com/urchin.js
passed: true, true, true, true, true
Failed
url: https://google-analytics.com/urchin.js
passed: false, false, false, false, false
Passed
url: https://google-analytics.com/urchin.js
passed: true, true, true, true, true
Failed
url: https://google-analytics.com/urchin.js
passed: false, false, false, false, false
Failed
url: https://google-analytics.com/urchin.js
passed: false, false, false, false, false
Passed
url: https://google-analytics.com/urchin.js
passed: true, true, true, true, true
Failed
url: https://google-analytics.com/urchin.js
passed: false, false, false, false, false
Passed
url: https://google-analytics.com/urchin.js
passed: true, true, true, true, true
Failed
url: https://google-analytics.com/urchin.js
passed: false, false, false, false, false
Failed
url: https://google-analytics.com/urchin.js
passed: false
Google Tag Manager
Tests whether the browser blocks the page from loading the tracker at https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL
              
Passed
url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL
passed: true, true, true, true, true
Failed
url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL
passed: false, false, false, false, false
Passed
url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL
passed: true, true, true, true, true
Failed
url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL
passed: false, false, false, false, false
Failed
url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL
passed: false, false, false, false, false
Failed
url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL
passed: false, false, false, false, false
Failed
url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL
passed: false, false, false, false, false
Passed
url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL
passed: true, true, true, true, true
Failed
url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL
passed: false, false, false, false, false
Failed
url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL
passed: false
Index Exchange
Tests whether the browser blocks the page from loading the tracker at https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1
              
Passed
url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1
passed: true, true, true, true, true
Failed
url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1
passed: false, false, false, false, false
Passed
url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1
passed: true, true, true, true, true
Failed
url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1
passed: false, false, false, false, false
Failed
url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1
passed: false, false, false, false, false
Passed
url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1
passed: true, true, true, true, true
Passed
url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1
passed: true, true, true, true, true
Passed
url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1
passed: true, true, true, true, true
Failed
url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1
passed: false, false, false, false, false
Failed
url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1
passed: false
New Relic
Tests whether the browser blocks the page from loading the tracker at https://js-agent.newrelic.com/nr-1212.min.js
              
Passed
url: https://js-agent.newrelic.com/nr-1212.min.js
passed: true, true, true, true, true
Failed
url: https://js-agent.newrelic.com/nr-1212.min.js
passed: false, false, false, false, false
Passed
url: https://js-agent.newrelic.com/nr-1212.min.js
passed: true, true, true, true, true
Failed
url: https://js-agent.newrelic.com/nr-1212.min.js
passed: false, false, false, false, false
Failed
url: https://js-agent.newrelic.com/nr-1212.min.js
passed: false, false, false, false, false
Passed
url: https://js-agent.newrelic.com/nr-1212.min.js
passed: true, true, true, true, true
Failed
url: https://js-agent.newrelic.com/nr-1212.min.js
passed: false, false, false, false, false
Failed
url: https://js-agent.newrelic.com/nr-1212.min.js
passed: false, false, false, false, false
Failed
url: https://js-agent.newrelic.com/nr-1212.min.js
passed: false, false, false, false, false
Failed
url: https://js-agent.newrelic.com/nr-1212.min.js
passed: false
Quantcast
Tests whether the browser blocks the page from loading the tracker at https://pixel.quantserve.com/pixel
              
Passed
url: https://pixel.quantserve.com/pixel
passed: true, true, true, true, true
Failed
url: https://pixel.quantserve.com/pixel
passed: false, false, false, false, false
Passed
url: https://pixel.quantserve.com/pixel
passed: true, true, true, true, true
Failed
url: https://pixel.quantserve.com/pixel
passed: false, false, false, false, false
Failed
url: https://pixel.quantserve.com/pixel
passed: false, false, false, false, false
Passed
url: https://pixel.quantserve.com/pixel
passed: true, true, true, true, true
Failed
url: https://pixel.quantserve.com/pixel
passed: false, false, false, false, false
Passed
url: https://pixel.quantserve.com/pixel
passed: true, true, true, true, true
Failed
url: https://pixel.quantserve.com/pixel
passed: false, false, false, false, false
Failed
url: https://pixel.quantserve.com/pixel
passed: false
Scorecard Research Beacon
Tests whether the browser blocks the page from loading the tracker at https://sb.scorecardresearch.com/internal-c2/default/cs.js
              
Passed
url: https://sb.scorecardresearch.com/internal-c2/default/cs.js
passed: true, true, true, true, true
Failed
url: https://sb.scorecardresearch.com/internal-c2/default/cs.js
passed: false, false, false, false, false
Passed
url: https://sb.scorecardresearch.com/internal-c2/default/cs.js
passed: true, true, true, true, true
Failed
url: https://sb.scorecardresearch.com/internal-c2/default/cs.js
passed: false, false, false, false, false
Failed
url: https://sb.scorecardresearch.com/internal-c2/default/cs.js
passed: false, false, false, false, false
Passed
url: https://sb.scorecardresearch.com/internal-c2/default/cs.js
passed: true, true, true, true, true
Failed
url: https://sb.scorecardresearch.com/internal-c2/default/cs.js
passed: false, false, false, false, false
Failed
url: https://sb.scorecardresearch.com/internal-c2/default/cs.js
passed: false, false, false, false, false
Failed
url: https://sb.scorecardresearch.com/internal-c2/default/cs.js
passed: false, false, false, false, false
Failed
url: https://sb.scorecardresearch.com/internal-c2/default/cs.js
passed: false
Taboola
Tests whether the browser blocks the page from loading the tracker at https://trc.taboola.com/futureplc-tomsguide/trc/3/json
              
Passed
url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json
passed: true, true, true, true, true
Failed
url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json
passed: false, false, false, false, false
Passed
url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json
passed: true, true, true, true, true
Failed
url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json
passed: false, false, false, false, false
Failed
url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json
passed: false, false, false, false, false
Passed
url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json
passed: true, true, true, true, true
Failed
url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json
passed: false, false, false, false, false
Failed
url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json
passed: false, false, false, false, false
Failed
url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json
passed: false, false, false, false, false
Failed
url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json
passed: false
Twitter pixel
Tests whether the browser blocks the page from loading the tracker at https://t.co/i/adsct
              
Passed
url: https://t.co/i/adsct
passed: true, true, true, true, true
Failed
url: https://t.co/i/adsct
passed: false, false, false, false, false
Passed
url: https://t.co/i/adsct
passed: true, true, true, true, true
Failed
url: https://t.co/i/adsct
passed: false, false, false, false, false
Failed
url: https://t.co/i/adsct
passed: false, false, false, false, false
Failed
url: https://t.co/i/adsct
passed: false, false, false, false, false
Failed
url: https://t.co/i/adsct
passed: false, false, false, false, false
Failed
url: https://t.co/i/adsct
passed: false, false, false, false, false
Failed
url: https://t.co/i/adsct
passed: false, false, false, false, false
Failed
url: https://t.co/i/adsct
passed: false
Yandex Ads
Tests whether the browser blocks the page from loading the tracker at https://yandex.ru/ads/system/header-bidding.js
              
Passed
url: https://yandex.ru/ads/system/header-bidding.js
passed: true, true, true, true, true
Failed
url: https://yandex.ru/ads/system/header-bidding.js
passed: false, false, false, false, false
Passed
url: https://yandex.ru/ads/system/header-bidding.js
passed: true, true, true, true, true
Failed
url: https://yandex.ru/ads/system/header-bidding.js
passed: false, false, false, false, false
Failed
url: https://yandex.ru/ads/system/header-bidding.js
passed: false, false, false, false, false
Failed
url: https://yandex.ru/ads/system/header-bidding.js
passed: false, false, false, false, false
Passed
url: https://yandex.ru/ads/system/header-bidding.js
passed: true, true, true, true, true
Failed
url: https://yandex.ru/ads/system/header-bidding.js
passed: false, false, false, false, false
Failed
url: https://yandex.ru/ads/system/header-bidding.js
passed: false, false, false, false, false
Failed
url: https://yandex.ru/ads/system/header-bidding.js
passed: false
Cross-session first-party tracking testsWhich browsers prevent websites from tracking you across browser sessions?
A common vulnerability of web browsers is that they allow websites ("first parties") to 'tag' your browser with some tracking data. This tag can be used to re-identify you when you return to a website you visited before. This category of leaks can be prevented by browser if they clean or isolate data between browser sessions. (In cases where a user has logged into a website or entered detailed information, it may be justifiable for a browser to retain information across sessions. These tests check when no such justification exists: when you have entered no significant information into a website, will the browser still retain data that allows you to be tracked across sessions?)
        
Alt-Svc
Alt-Svc allows the server to indicate to the web browser that a resource should be loaded on a different server. Because this is a persistent setting, it could be used to track users across websites if it is not correctly partitioned.
              
Passed
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2, h3, h2, h3, h2

result, different session: h3, h2, h3, h2, h3

unsupported: true, false, true, false, true

passed: , true, true

test failed: false, false, false, false, false
Passed
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2, h3, h2, h3, h2

result, different session: h3, h2, h3, h2, h3

unsupported: true, false, true, false, true

passed: , true, true

test failed: false, false, false, false, false
Passed
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2, h3, h2, h3, h2

result, different session: h3, h2, h3, h2, h3

unsupported: true, false, true, false, true

passed: , true, true

test failed: false, false, false, false, false
Passed
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2, h3, h2, h3, h2

result, different session: h3, h2, h3, h2, h3

unsupported: true, false, true, false, true

passed: , true, true

test failed: false, false, false, false, false
Passed
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h3, h2, h3, h2, h3

result, different session: h2, h3, h2, h3, h2

unsupported: false, true, false, true, false

passed: true, true, true

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2, h2, h2, h2, h2

result, different session: h2, h2, h2, h2, h2

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Passed
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2, h3, h2, h3, h2

result, different session: h3, h2, h3, h2, h3

unsupported: true, false, true, false, true

passed: , true, true

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2, h2, h2, h2, h2

result, different session: h2, h2, h2, h2, h2

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Passed
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2, h3, h2, h3, h2

result, different session: h3, h2, h3, h2, h3

unsupported: true, false, true, false, true

passed: , true, true

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2

result, different session: h2

unsupported: true

passed: undefined

test failed: false
CacheStorage
The Cache API is a content storage mechanism originally introduced to support ServiceWorkers. If the same Cache object is accessible to multiple websites, it can be abused to track users.
              
Failed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 
4c3c69ee-898c-4616-bf3b-e54d77ac14fd_1p,
4c3c69ee-898c-4616-bf3b-e54d77ac14fd_1p,
4c3c69ee-898c-4616-bf3b-e54d77ac14fd_1p,
4c3c69ee-898c-4616-bf3b-e54d77ac14fd_1p,
4c3c69ee-898c-4616-bf3b-e54d77ac14fd_1p

result, different session: 
4c3c69ee-898c-4616-bf3b-e54d77ac14fd_1p,
4c3c69ee-898c-4616-bf3b-e54d77ac14fd_1p,
4c3c69ee-898c-4616-bf3b-e54d77ac14fd_1p,
4c3c69ee-898c-4616-bf3b-e54d77ac14fd_1p,
4c3c69ee-898c-4616-bf3b-e54d77ac14fd_1p

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 
6ff0b878-e459-4077-873d-c4d73a8b4c3f_1p,
94d0ff49-2e50-4f68-a576-2f481a9b0dfb_1p,
db9ededa-3d85-49d1-b22f-66b9d13151e9_1p,
eda356c0-dfbb-48c4-98bc-e3060f20796d_1p,
45855e06-c12b-4c97-a80f-b05d0634705e_1p

result, different session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_1p,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_1p,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_1p,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_1p,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_1p

result, different session: 
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_1p,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_1p,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_1p,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_1p,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_1p

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 
9f1a20c0-3f9c-4aa5-8aa8-e56950e57e74_1p,
e4fef07d-00dc-4960-8421-eaed44851eed_1p,
154af211-304d-45c2-bd1d-edfcf6a953c2_1p,
bbc94382-8354-43fa-9caa-06c72e77a772_1p,
5cd2be12-be84-4ee2-ad4f-e8bd13d52186_1p

result, different session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 
a09b69c9-0216-4504-9061-fc5c61dd3c23_1p,
7b6315a4-06ef-4ac0-8f42-ce400041b707_1p,
2d5c9ed0-3dbd-48e7-84ef-eb6e8484cdbf_1p,
65902525-09ad-4c46-865a-d3fc1f63ac7b_1p,
6e3bb471-c66f-4f24-8437-1dbee8645c0e_1p

result, different session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

result, different session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 
213faa81-9820-4e64-8ca2-4b2c56e0fd16_1p,
cf7391f7-aa80-401f-81c4-7c2508844631_1p,
6cb5025c-2699-446a-9372-39087b296a21_1p,
9a0e433f-dc60-4ba4-ba79-fa1ff3caccb5_1p,
4335c2dd-8867-446f-8184-bd81aa0654b6_1p

result, different session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

result, different session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 
b4e6c154-78d4-4ea8-9de8-7342f2b90461_1p,
a938646f-4e8a-409b-8a23-9aa66b47e388_1p,
26e63861-906d-420b-bba7-f80b45898c34_1p,
cda34f43-1255-481b-9e0d-1c216b86d6fa_1p,
6779afe3-026e-4315-87e0-9c8f43f3c72c_1p

result, different session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 9a23f54f-1c25-4d46-96c2-662562228a7a_1p

result, different session: 9a23f54f-1c25-4d46-96c2-662562228a7a_1p

unsupported: false

passed: false

test failed: false
cookie (HTTP)
The cookie, first introduced by Netscape in 1994, is a small amount of data stored by your browser on a website's behalf. It has legitimate uses, but it is also the classic cross-site tracking mechanism, and today still the most popular method of tracking users across websites. Browsers can stop cookies from being used for cross-site tracking by either blocking or partitioning them.
              
Failed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: 
4bde1512-0784-43fb-887a-56a509216ec5_1p_http,
41005147-8107-4a0f-bd00-5de04892fc40_1p_http,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1_1p_http,
bcde0d87-19c8-4d11-b69d-cf5b05adac32_1p_http,
cf7b9801-6b0c-4efc-9361-c923491dbafc_1p_http

result, different session: 
4bde1512-0784-43fb-887a-56a509216ec5_1p_http,
41005147-8107-4a0f-bd00-5de04892fc40_1p_http,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1_1p_http,
bcde0d87-19c8-4d11-b69d-cf5b05adac32_1p_http,
cf7b9801-6b0c-4efc-9361-c923491dbafc_1p_http

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: 
6ff0b878-e459-4077-873d-c4d73a8b4c3f_1p_http,
94d0ff49-2e50-4f68-a576-2f481a9b0dfb_1p_http,
db9ededa-3d85-49d1-b22f-66b9d13151e9_1p_http,
eda356c0-dfbb-48c4-98bc-e3060f20796d_1p_http,
45855e06-c12b-4c97-a80f-b05d0634705e_1p_http

result, different session: 
6ff0b878-e459-4077-873d-c4d73a8b4c3f_1p_http,
94d0ff49-2e50-4f68-a576-2f481a9b0dfb_1p_http,
db9ededa-3d85-49d1-b22f-66b9d13151e9_1p_http,
eda356c0-dfbb-48c4-98bc-e3060f20796d_1p_http,
45855e06-c12b-4c97-a80f-b05d0634705e_1p_http

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: 
58109673-6b30-4c3c-93dc-9f3935edeced_1p_http,
2aa2bf6f-0a07-4a35-ae45-e9b6a1d11e20_1p_http,
732a589c-ffa1-441f-b046-e96ae5ecce3b_1p_http,
be322cbd-9046-492a-8283-325c7e6e36ca_1p_http,
4d80e8ed-2942-4e43-80e6-7e11a7e16883_1p_http

result, different session: 
58109673-6b30-4c3c-93dc-9f3935edeced_1p_http,
2aa2bf6f-0a07-4a35-ae45-e9b6a1d11e20_1p_http,
732a589c-ffa1-441f-b046-e96ae5ecce3b_1p_http,
be322cbd-9046-492a-8283-325c7e6e36ca_1p_http,
4d80e8ed-2942-4e43-80e6-7e11a7e16883_1p_http

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: 
9f1a20c0-3f9c-4aa5-8aa8-e56950e57e74_1p_http,
e4fef07d-00dc-4960-8421-eaed44851eed_1p_http,
154af211-304d-45c2-bd1d-edfcf6a953c2_1p_http,
bbc94382-8354-43fa-9caa-06c72e77a772_1p_http,
5cd2be12-be84-4ee2-ad4f-e8bd13d52186_1p_http

result, different session: 
9f1a20c0-3f9c-4aa5-8aa8-e56950e57e74_1p_http,
e4fef07d-00dc-4960-8421-eaed44851eed_1p_http,
154af211-304d-45c2-bd1d-edfcf6a953c2_1p_http,
bbc94382-8354-43fa-9caa-06c72e77a772_1p_http,
5cd2be12-be84-4ee2-ad4f-e8bd13d52186_1p_http

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: 
a09b69c9-0216-4504-9061-fc5c61dd3c23_1p_http,
7b6315a4-06ef-4ac0-8f42-ce400041b707_1p_http,
2d5c9ed0-3dbd-48e7-84ef-eb6e8484cdbf_1p_http,
65902525-09ad-4c46-865a-d3fc1f63ac7b_1p_http,
6e3bb471-c66f-4f24-8437-1dbee8645c0e_1p_http

result, different session: 
a09b69c9-0216-4504-9061-fc5c61dd3c23_1p_http,
7b6315a4-06ef-4ac0-8f42-ce400041b707_1p_http,
2d5c9ed0-3dbd-48e7-84ef-eb6e8484cdbf_1p_http,
65902525-09ad-4c46-865a-d3fc1f63ac7b_1p_http,
6e3bb471-c66f-4f24-8437-1dbee8645c0e_1p_http

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: 
c4e8c0f1-6882-4a88-b2b0-1abda72db45e_1p_http,
ae52c0dc-9b2c-4efd-9348-d816b188d956_1p_http,
9d44a7cf-1964-4a73-81b3-b7941a1a8e4d_1p_http,
3a9a3eda-7e51-42b7-9ccf-5557bf5b9c77_1p_http,
896b9c56-96e4-44cb-9a3b-76bd875cead7_1p_http

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: 
213faa81-9820-4e64-8ca2-4b2c56e0fd16_1p_http,
cf7391f7-aa80-401f-81c4-7c2508844631_1p_http,
6cb5025c-2699-446a-9372-39087b296a21_1p_http,
9a0e433f-dc60-4ba4-ba79-fa1ff3caccb5_1p_http,
4335c2dd-8867-446f-8184-bd81aa0654b6_1p_http

result, different session: 
213faa81-9820-4e64-8ca2-4b2c56e0fd16_1p_http,
cf7391f7-aa80-401f-81c4-7c2508844631_1p_http,
6cb5025c-2699-446a-9372-39087b296a21_1p_http,
9a0e433f-dc60-4ba4-ba79-fa1ff3caccb5_1p_http,
4335c2dd-8867-446f-8184-bd81aa0654b6_1p_http

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: 
1e854cf6-6d0d-4987-b89f-4f0e6bfb3013_1p_http,
2485a3ce-aa3e-4197-ba4a-2835da79e7ac_1p_http,
f8e56e03-da27-4aae-9eee-18c4b864da6a_1p_http,
63fc99e9-1362-4918-9b98-fd62c233cfaf_1p_http,
7fe7e385-59f1-4ded-a894-f9710f27446e_1p_http

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: 
b4e6c154-78d4-4ea8-9de8-7342f2b90461_1p_http,
a938646f-4e8a-409b-8a23-9aa66b47e388_1p_http,
26e63861-906d-420b-bba7-f80b45898c34_1p_http,
cda34f43-1255-481b-9e0d-1c216b86d6fa_1p_http,
6779afe3-026e-4315-87e0-9c8f43f3c72c_1p_http

result, different session: 
b4e6c154-78d4-4ea8-9de8-7342f2b90461_1p_http,
a938646f-4e8a-409b-8a23-9aa66b47e388_1p_http,
26e63861-906d-420b-bba7-f80b45898c34_1p_http,
cda34f43-1255-481b-9e0d-1c216b86d6fa_1p_http,
6779afe3-026e-4315-87e0-9c8f43f3c72c_1p_http

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: 40268717-416c-4353-9311-83b6625eb429_1p_http

result, different session: 40268717-416c-4353-9311-83b6625eb429_1p_http

unsupported: false

passed: false

test failed: false
cookie (JS)
The cookie, first introduced by Netscape in 1994, is a small amount of data stored by your browser on a website's behalf. It has legitimate uses, but it is also the classic cross-site tracking mechanism, and today still the most popular method of tracking users across websites. Browsers can stop cookies from being used for cross-site tracking by either blocking or partitioning them.
              
Failed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: 
4bde1512-0784-43fb-887a-56a509216ec5_1p_js,
41005147-8107-4a0f-bd00-5de04892fc40_1p_js,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1_1p_js,
bcde0d87-19c8-4d11-b69d-cf5b05adac32_1p_js,
cf7b9801-6b0c-4efc-9361-c923491dbafc_1p_js

result, different session: 
4bde1512-0784-43fb-887a-56a509216ec5_1p_js,
41005147-8107-4a0f-bd00-5de04892fc40_1p_js,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1_1p_js,
bcde0d87-19c8-4d11-b69d-cf5b05adac32_1p_js,
cf7b9801-6b0c-4efc-9361-c923491dbafc_1p_js

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: 
6ff0b878-e459-4077-873d-c4d73a8b4c3f_1p_js,
94d0ff49-2e50-4f68-a576-2f481a9b0dfb_1p_js,
db9ededa-3d85-49d1-b22f-66b9d13151e9_1p_js,
eda356c0-dfbb-48c4-98bc-e3060f20796d_1p_js,
45855e06-c12b-4c97-a80f-b05d0634705e_1p_js

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: 
58109673-6b30-4c3c-93dc-9f3935edeced_1p_js,
2aa2bf6f-0a07-4a35-ae45-e9b6a1d11e20_1p_js,
732a589c-ffa1-441f-b046-e96ae5ecce3b_1p_js,
be322cbd-9046-492a-8283-325c7e6e36ca_1p_js,
4d80e8ed-2942-4e43-80e6-7e11a7e16883_1p_js

result, different session: 
58109673-6b30-4c3c-93dc-9f3935edeced_1p_js,
2aa2bf6f-0a07-4a35-ae45-e9b6a1d11e20_1p_js,
732a589c-ffa1-441f-b046-e96ae5ecce3b_1p_js,
be322cbd-9046-492a-8283-325c7e6e36ca_1p_js,
4d80e8ed-2942-4e43-80e6-7e11a7e16883_1p_js

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: 
9f1a20c0-3f9c-4aa5-8aa8-e56950e57e74_1p_js,
e4fef07d-00dc-4960-8421-eaed44851eed_1p_js,
154af211-304d-45c2-bd1d-edfcf6a953c2_1p_js,
bbc94382-8354-43fa-9caa-06c72e77a772_1p_js,
5cd2be12-be84-4ee2-ad4f-e8bd13d52186_1p_js

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: 
a09b69c9-0216-4504-9061-fc5c61dd3c23_1p_js,
7b6315a4-06ef-4ac0-8f42-ce400041b707_1p_js,
2d5c9ed0-3dbd-48e7-84ef-eb6e8484cdbf_1p_js,
65902525-09ad-4c46-865a-d3fc1f63ac7b_1p_js,
6e3bb471-c66f-4f24-8437-1dbee8645c0e_1p_js

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: 
c4e8c0f1-6882-4a88-b2b0-1abda72db45e_1p_js,
ae52c0dc-9b2c-4efd-9348-d816b188d956_1p_js,
9d44a7cf-1964-4a73-81b3-b7941a1a8e4d_1p_js,
3a9a3eda-7e51-42b7-9ccf-5557bf5b9c77_1p_js,
896b9c56-96e4-44cb-9a3b-76bd875cead7_1p_js

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: 
213faa81-9820-4e64-8ca2-4b2c56e0fd16_1p_js,
cf7391f7-aa80-401f-81c4-7c2508844631_1p_js,
6cb5025c-2699-446a-9372-39087b296a21_1p_js,
9a0e433f-dc60-4ba4-ba79-fa1ff3caccb5_1p_js,
4335c2dd-8867-446f-8184-bd81aa0654b6_1p_js

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: 
1e854cf6-6d0d-4987-b89f-4f0e6bfb3013_1p_js,
2485a3ce-aa3e-4197-ba4a-2835da79e7ac_1p_js,
f8e56e03-da27-4aae-9eee-18c4b864da6a_1p_js,
63fc99e9-1362-4918-9b98-fd62c233cfaf_1p_js,
7fe7e385-59f1-4ded-a894-f9710f27446e_1p_js

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: 
b4e6c154-78d4-4ea8-9de8-7342f2b90461_1p_js,
a938646f-4e8a-409b-8a23-9aa66b47e388_1p_js,
26e63861-906d-420b-bba7-f80b45898c34_1p_js,
cda34f43-1255-481b-9e0d-1c216b86d6fa_1p_js,
6779afe3-026e-4315-87e0-9c8f43f3c72c_1p_js

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: 40268717-416c-4353-9311-83b6625eb429_1p_js

result, different session: 40268717-416c-4353-9311-83b6625eb429_1p_js

unsupported: false

passed: false

test failed: false
CookieStore
The Cookie Store API is an alternative asynchronous API for managing cookies, supported by some browsers.
              
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: Error: Unsupported

result, different session: Error: Unsupported

unsupported: true

passed: undefined

test failed: false
CSS cache
CSS stylesheets are cached, and if that cache is shared between websites, it can be used to track users across sites.
              
Failed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: 
fake_7482943602713723,
fake_9276518921507779,
fake_8486259136782022,
fake_4107859936558087,
fake_08982515075538822

result, different session: 
fake_7482943602713723,
fake_9276518921507779,
fake_8486259136782022,
fake_4107859936558087,
fake_08982515075538822

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: 
fake_1726761770015548,
fake_2824773876279474,
fake_6518265797407512,
fake_4484931027716812,
fake_8604410160109541

result, different session: 
fake_1726761770015548,
fake_2824773876279474,
fake_6518265797407512,
fake_4484931027716812,
fake_8604410160109541

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: 
fake_32021433089337537,
fake_011239856303290052,
fake_32341016812221524,
fake_36488435195973823,
fake_5468729570124291

result, different session: 
fake_32021433089337537,
fake_011239856303290052,
fake_32341016812221524,
fake_36488435195973823,
fake_5468729570124291

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: 
fake_6507600487133198,
fake_33771027792190744,
fake_8335761779003095,
fake_8486434662207418,
fake_5458163035389685

result, different session: 
fake_6507600487133198,
fake_33771027792190744,
fake_8335761779003095,
fake_8486434662207418,
fake_5458163035389685

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: 
fake_5077232587012157,
fake_159214234559224,
fake_7720914855795902,
fake_337040468076254,
fake_5466367618192847

result, different session: 
fake_5077232587012157,
fake_159214234559224,
fake_7720914855795902,
fake_337040468076254,
fake_5466367618192847

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: 
fake_5681124265512878,
fake_7310157584499162,
fake_7607567438826495,
fake_6616383707559648,
fake_2194496516562945

result, different session: 
fake_07292818222177422,
fake_19900606310738977,
fake_6995569973903084,
fake_32500127534064926,
fake_38665108466067855

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: 
fake_0048787633263112085,
fake_24575915643861945,
fake_483452266808964,
fake_38311089577922686,
fake_6012960693623461

result, different session: 
fake_0048787633263112085,
fake_24575915643861945,
fake_483452266808964,
fake_38311089577922686,
fake_6012960693623461

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: 
fake_8970738151120758,
fake_685218293299753,
fake_30125200764583226,
fake_9152574560614508,
fake_8098631174881534

result, different session: 
fake_3309525628654191,
fake_29786283024977545,
fake_7088315773193798,
fake_5583763405277378,
fake_5556618895598888

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: 
fake_025171035818289278,
fake_7880776456599734,
fake_23325376572057688,
fake_7152614779179498,
fake_23869164155419242

result, different session: 
fake_025171035818289278,
fake_7880776456599734,
fake_23325376572057688,
fake_7152614779179498,
fake_23869164155419242

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: fake_2374747752404216

result, different session: fake_8426213088395882

unsupported: false

passed: true

test failed: false
favicon cache
A favicon is an icon that represents a website, typically shown in browser tab and bookmarks menu. If the favicon cache is not partitioned, it can be used to track users across websites.
              
Failed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Unsupported
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Failed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Unsupported
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Failed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 2, 1, 1, 1, 2

result, different session: 2, 1, 1, 1, 2

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 1

result, different session: 1

unsupported: false

passed: false

test failed: false
fetch cache
When a resource is received via the Fetch API, it is frequently cached. That cache can potentially be abused for cross-site tracking.
              
Failed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 2, 2, 2, 2, 2

result, different session: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 2, 2, 2, 2, 2

result, different session: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1

result, different session: 2

unsupported: false

passed: true

test failed: false
font cache
Web fonts are sometimes stored in their own cache, which is vulnerable to being abused for cross-site tracking.
              
Failed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1

result, different session: 2

unsupported: false

passed: true

test failed: false
iframe cache
An iframe is an element in a web page than allows websites to embed a second web page. Caching of this web page could be abused for cross-site tracking.
              
Failed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1

result, different session: 2

unsupported: false

passed: true

test failed: false
image cache
Caching of images in web browsers is a standard behavior. But if that cache leaks between websites, it can be abused for cross-site tracking.
              
Failed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1

result, different session: 2

unsupported: false

passed: true

test failed: false
indexedDB
The IndexedDB API exposes a transactional database to web pages. That database can be used to track users across websites, unless it is partitioned.
              
Failed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 
4bde1512-0784-43fb-887a-56a509216ec5_1p,
41005147-8107-4a0f-bd00-5de04892fc40_1p,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1_1p,
bcde0d87-19c8-4d11-b69d-cf5b05adac32_1p,
cf7b9801-6b0c-4efc-9361-c923491dbafc_1p

result, different session: 
4bde1512-0784-43fb-887a-56a509216ec5_1p,
41005147-8107-4a0f-bd00-5de04892fc40_1p,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1_1p,
bcde0d87-19c8-4d11-b69d-cf5b05adac32_1p,
cf7b9801-6b0c-4efc-9361-c923491dbafc_1p

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 
6ff0b878-e459-4077-873d-c4d73a8b4c3f_1p,
94d0ff49-2e50-4f68-a576-2f481a9b0dfb_1p,
db9ededa-3d85-49d1-b22f-66b9d13151e9_1p,
eda356c0-dfbb-48c4-98bc-e3060f20796d_1p,
45855e06-c12b-4c97-a80f-b05d0634705e_1p

result, different session: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 
58109673-6b30-4c3c-93dc-9f3935edeced_1p,
2aa2bf6f-0a07-4a35-ae45-e9b6a1d11e20_1p,
732a589c-ffa1-441f-b046-e96ae5ecce3b_1p,
be322cbd-9046-492a-8283-325c7e6e36ca_1p,
4d80e8ed-2942-4e43-80e6-7e11a7e16883_1p

result, different session: 
58109673-6b30-4c3c-93dc-9f3935edeced_1p,
2aa2bf6f-0a07-4a35-ae45-e9b6a1d11e20_1p,
732a589c-ffa1-441f-b046-e96ae5ecce3b_1p,
be322cbd-9046-492a-8283-325c7e6e36ca_1p,
4d80e8ed-2942-4e43-80e6-7e11a7e16883_1p

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 
9f1a20c0-3f9c-4aa5-8aa8-e56950e57e74_1p,
e4fef07d-00dc-4960-8421-eaed44851eed_1p,
154af211-304d-45c2-bd1d-edfcf6a953c2_1p,
bbc94382-8354-43fa-9caa-06c72e77a772_1p,
5cd2be12-be84-4ee2-ad4f-e8bd13d52186_1p

result, different session: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 
a09b69c9-0216-4504-9061-fc5c61dd3c23_1p,
7b6315a4-06ef-4ac0-8f42-ce400041b707_1p,
2d5c9ed0-3dbd-48e7-84ef-eb6e8484cdbf_1p,
65902525-09ad-4c46-865a-d3fc1f63ac7b_1p,
6e3bb471-c66f-4f24-8437-1dbee8645c0e_1p

result, different session: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 
c4e8c0f1-6882-4a88-b2b0-1abda72db45e_1p,
ae52c0dc-9b2c-4efd-9348-d816b188d956_1p,
9d44a7cf-1964-4a73-81b3-b7941a1a8e4d_1p,
3a9a3eda-7e51-42b7-9ccf-5557bf5b9c77_1p,
896b9c56-96e4-44cb-9a3b-76bd875cead7_1p

result, different session: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 
213faa81-9820-4e64-8ca2-4b2c56e0fd16_1p,
cf7391f7-aa80-401f-81c4-7c2508844631_1p,
6cb5025c-2699-446a-9372-39087b296a21_1p,
9a0e433f-dc60-4ba4-ba79-fa1ff3caccb5_1p,
4335c2dd-8867-446f-8184-bd81aa0654b6_1p

result, different session: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 
1e854cf6-6d0d-4987-b89f-4f0e6bfb3013_1p,
2485a3ce-aa3e-4197-ba4a-2835da79e7ac_1p,
f8e56e03-da27-4aae-9eee-18c4b864da6a_1p,
63fc99e9-1362-4918-9b98-fd62c233cfaf_1p,
7fe7e385-59f1-4ded-a894-f9710f27446e_1p

result, different session: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 
b4e6c154-78d4-4ea8-9de8-7342f2b90461_1p,
a938646f-4e8a-409b-8a23-9aa66b47e388_1p,
26e63861-906d-420b-bba7-f80b45898c34_1p,
cda34f43-1255-481b-9e0d-1c216b86d6fa_1p,
6779afe3-026e-4315-87e0-9c8f43f3c72c_1p

result, different session: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 40268717-416c-4353-9311-83b6625eb429_1p

result, different session: 40268717-416c-4353-9311-83b6625eb429_1p

unsupported: false

passed: false

test failed: false
localStorage
The localStorage API gives websites access to a key-value database that will remain available across visits. If the localStorage API is not partitioned or blocked, it can also be used to track users across websites.
              
Failed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 
4bde1512-0784-43fb-887a-56a509216ec5_1p,
41005147-8107-4a0f-bd00-5de04892fc40_1p,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1_1p,
bcde0d87-19c8-4d11-b69d-cf5b05adac32_1p,
cf7b9801-6b0c-4efc-9361-c923491dbafc_1p

result, different session: 
4bde1512-0784-43fb-887a-56a509216ec5_1p,
41005147-8107-4a0f-bd00-5de04892fc40_1p,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1_1p,
bcde0d87-19c8-4d11-b69d-cf5b05adac32_1p,
cf7b9801-6b0c-4efc-9361-c923491dbafc_1p

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 
6ff0b878-e459-4077-873d-c4d73a8b4c3f_1p,
94d0ff49-2e50-4f68-a576-2f481a9b0dfb_1p,
db9ededa-3d85-49d1-b22f-66b9d13151e9_1p,
eda356c0-dfbb-48c4-98bc-e3060f20796d_1p,
45855e06-c12b-4c97-a80f-b05d0634705e_1p

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 
58109673-6b30-4c3c-93dc-9f3935edeced_1p,
2aa2bf6f-0a07-4a35-ae45-e9b6a1d11e20_1p,
732a589c-ffa1-441f-b046-e96ae5ecce3b_1p,
be322cbd-9046-492a-8283-325c7e6e36ca_1p,
4d80e8ed-2942-4e43-80e6-7e11a7e16883_1p

result, different session: 
58109673-6b30-4c3c-93dc-9f3935edeced_1p,
2aa2bf6f-0a07-4a35-ae45-e9b6a1d11e20_1p,
732a589c-ffa1-441f-b046-e96ae5ecce3b_1p,
be322cbd-9046-492a-8283-325c7e6e36ca_1p,
4d80e8ed-2942-4e43-80e6-7e11a7e16883_1p

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 
9f1a20c0-3f9c-4aa5-8aa8-e56950e57e74_1p,
e4fef07d-00dc-4960-8421-eaed44851eed_1p,
154af211-304d-45c2-bd1d-edfcf6a953c2_1p,
bbc94382-8354-43fa-9caa-06c72e77a772_1p,
5cd2be12-be84-4ee2-ad4f-e8bd13d52186_1p

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 
a09b69c9-0216-4504-9061-fc5c61dd3c23_1p,
7b6315a4-06ef-4ac0-8f42-ce400041b707_1p,
2d5c9ed0-3dbd-48e7-84ef-eb6e8484cdbf_1p,
65902525-09ad-4c46-865a-d3fc1f63ac7b_1p,
6e3bb471-c66f-4f24-8437-1dbee8645c0e_1p

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 
c4e8c0f1-6882-4a88-b2b0-1abda72db45e_1p,
ae52c0dc-9b2c-4efd-9348-d816b188d956_1p,
9d44a7cf-1964-4a73-81b3-b7941a1a8e4d_1p,
3a9a3eda-7e51-42b7-9ccf-5557bf5b9c77_1p,
896b9c56-96e4-44cb-9a3b-76bd875cead7_1p

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 
213faa81-9820-4e64-8ca2-4b2c56e0fd16_1p,
cf7391f7-aa80-401f-81c4-7c2508844631_1p,
6cb5025c-2699-446a-9372-39087b296a21_1p,
9a0e433f-dc60-4ba4-ba79-fa1ff3caccb5_1p,
4335c2dd-8867-446f-8184-bd81aa0654b6_1p

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 
1e854cf6-6d0d-4987-b89f-4f0e6bfb3013_1p,
2485a3ce-aa3e-4197-ba4a-2835da79e7ac_1p,
f8e56e03-da27-4aae-9eee-18c4b864da6a_1p,
63fc99e9-1362-4918-9b98-fd62c233cfaf_1p,
7fe7e385-59f1-4ded-a894-f9710f27446e_1p

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 
b4e6c154-78d4-4ea8-9de8-7342f2b90461_1p,
a938646f-4e8a-409b-8a23-9aa66b47e388_1p,
26e63861-906d-420b-bba7-f80b45898c34_1p,
cda34f43-1255-481b-9e0d-1c216b86d6fa_1p,
6779afe3-026e-4315-87e0-9c8f43f3c72c_1p

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 40268717-416c-4353-9311-83b6625eb429_1p

result, different session: 40268717-416c-4353-9311-83b6625eb429_1p

unsupported: false

passed: false

test failed: false
prefetch cache
A <link rel='prefetch'...> suggests to browsers they should fetch a resource ahead of time and cache it. But if browsers don't partition this cache, it can be used to track users across websites.
              
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: Error: No requests received

result, different session: Error: No requests received

unsupported: true

passed: undefined

test failed: false
script cache
Caching of scripts in web browsers is a standard behavior. But if that cache leaks between websites, it can be abused for cross-site tracking.
              
Failed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1

result, different session: 2

unsupported: false

passed: true

test failed: false
XMLHttpRequest cache
Similar to the newer Fetch API, any resource received may be cached by the browser. The cache is potentially vulnerable to cross-site tracking attack.
              
Failed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1

result, different session: 2

unsupported: false

passed: true

test failed: false
Cross-session third-party tracking testsWhich browsers prevent third-party trackers from tracking you across browser sessions?
A common vulnerability of web browsers is that they allow third-party trackers to 'tag' your browser with some tracking data. This tag can be used to re-identify you when you return to a website you visited before. This category of leaks can be prevented by browser if they clean or isolate data between browser sessions. (In cases where a user has logged into a website or entered detailed information, it may be justifiable for a browser to retain information across sessions. These tests check when no such justification exists: when you have entered no significant information into a website, will the browser still retain data that allows you to be tracked across sessions?)
        
Alt-Svc
Alt-Svc allows the server to indicate to the web browser that a resource should be loaded on a different server. Because this is a persistent setting, it could be used to track users across websites if it is not correctly partitioned.
              
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2, h2, h2, h2, h2

result, different session: h3, h3, h3, h3, h3

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2, h2, h2, h2, h2

result, different session: h3, h3, h3, h3, h3

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2, h2, h2, h2, h2

result, different session: h3, h3, h3, h3, h3

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2, h2, h2, h2, h2

result, different session: h3, h3, h3, h3, h3

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2, h2, h2, h2, h2

result, different session: h3, h3, h3, h3, h3

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2, h2, h2, h2, h2

result, different session: h2, h2, h2, h2, h2

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2, h2, h2, h2, h2

result, different session: h3, h3, h3, h3, h3

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2, h2, h2, h2, h2

result, different session: h2, h2, h2, h2, h2

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2, h2, h2, h2, h2

result, different session: h3, h3, h3, h3, h3

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async () => {
      // Clear Alt-Svc caching first.
      let responseText = "";
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/clear");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after clear:", responseText);
      // Store "h3" state in Alt-Svc cache
      for (let i = 0; i < 3; ++i) {
        await fetch(altSvcOrigin + "/set");
        await sleepMs(100);
      }
      responseText = await fetchText(altSvcOrigin + "/protocol");
      console.log("after set:", responseText);
    }

read: async () => {
      const protocol = await fetchText(altSvcOrigin + "/protocol");
      if ((new URL(location)).searchParams.get("thirdparty") === "same") {
        if (protocol !== "h3") {
          throw new Error("Unsupported");
        }
      }
      return protocol;
    }

result, same session: h2

result, different session: h2

unsupported: true

passed: undefined

test failed: false
CacheStorage
The Cache API is a content storage mechanism originally introduced to support ServiceWorkers. If the same Cache object is accessible to multiple websites, it can be abused to track users.
              
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 
4bde1512-0784-43fb-887a-56a509216ec5_3p,
41005147-8107-4a0f-bd00-5de04892fc40_3p,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1_3p,
bcde0d87-19c8-4d11-b69d-cf5b05adac32_3p,
cf7b9801-6b0c-4efc-9361-c923491dbafc_3p

result, different session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 
6ff0b878-e459-4077-873d-c4d73a8b4c3f_3p,
94d0ff49-2e50-4f68-a576-2f481a9b0dfb_3p,
db9ededa-3d85-49d1-b22f-66b9d13151e9_3p,
eda356c0-dfbb-48c4-98bc-e3060f20796d_3p,
45855e06-c12b-4c97-a80f-b05d0634705e_3p

result, different session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_3p,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_3p,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_3p,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_3p,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_3p

result, different session: 
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_3p,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_3p,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_3p,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_3p,
c846cb44-12d2-41b3-b2a6-38ca1a4518ed_3p

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 
9f1a20c0-3f9c-4aa5-8aa8-e56950e57e74_3p,
e4fef07d-00dc-4960-8421-eaed44851eed_3p,
154af211-304d-45c2-bd1d-edfcf6a953c2_3p,
bbc94382-8354-43fa-9caa-06c72e77a772_3p,
5cd2be12-be84-4ee2-ad4f-e8bd13d52186_3p

result, different session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 
a09b69c9-0216-4504-9061-fc5c61dd3c23_3p,
7b6315a4-06ef-4ac0-8f42-ce400041b707_3p,
2d5c9ed0-3dbd-48e7-84ef-eb6e8484cdbf_3p,
65902525-09ad-4c46-865a-d3fc1f63ac7b_3p,
6e3bb471-c66f-4f24-8437-1dbee8645c0e_3p

result, different session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

result, different session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 
213faa81-9820-4e64-8ca2-4b2c56e0fd16_3p,
cf7391f7-aa80-401f-81c4-7c2508844631_3p,
6cb5025c-2699-446a-9372-39087b296a21_3p,
9a0e433f-dc60-4ba4-ba79-fa1ff3caccb5_3p,
4335c2dd-8867-446f-8184-bd81aa0654b6_3p

result, different session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

result, different session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Passed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 
b4e6c154-78d4-4ea8-9de8-7342f2b90461_3p,
a938646f-4e8a-409b-8a23-9aa66b47e388_3p,
26e63861-906d-420b-bba7-f80b45898c34_3p,
cda34f43-1255-481b-9e0d-1c216b86d6fa_3p,
6779afe3-026e-4315-87e0-9c8f43f3c72c_3p

result, different session: 
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url'),
Error: undefined is not an object (evaluating 'cacheKeys[0].url')

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      try {
        let cache = await caches.open("supercookies");
        cache.addAll([`test.css?key=${key}`]);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: async () => {
      let cache = await caches.open("supercookies");
      let cacheKeys = await cache.keys();
      let url = cacheKeys[0].url;
      return (new URL(url)).searchParams.get("key");
    }

result, same session: 78486d2e-369d-4466-9c9b-7ed55aa72ecd_3p

result, different session: 78486d2e-369d-4466-9c9b-7ed55aa72ecd_3p

unsupported: false

passed: false

test failed: false
cookie (HTTP)
The cookie, first introduced by Netscape in 1994, is a small amount of data stored by your browser on a website's behalf. It has legitimate uses, but it is also the classic cross-site tracking mechanism, and today still the most popular method of tracking users across websites. Browsers can stop cookies from being used for cross-site tracking by either blocking or partitioning them.
              
Unsupported
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: , , , , 

result, different session: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: , , , , 

result, different session: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: , , , , 

result, different session: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: , , , , 

result, different session: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: , , , , 

result, different session: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: , , , , 

result, different session: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: , , , , 

result, different session: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: , , , , 

result, different session: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: , , , , 

result, different session: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (secret) => {
      // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value.
      await fetch(`${baseURI}cookie?secret=${secret}_http`);
    }

read: async () => {
      // Test if we now send a requests with a 'cookie' header containing the secret.
      let response = await fetch(`${baseURI}headers`);
      let cookie = (await response.json())["cookie"];
      return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null;
    }

result, same session: null

result, different session: null

unsupported: true

passed: undefined

test failed: false
cookie (JS)
The cookie, first introduced by Netscape in 1994, is a small amount of data stored by your browser on a website's behalf. It has legitimate uses, but it is also the classic cross-site tracking mechanism, and today still the most popular method of tracking users across websites. Browsers can stop cookies from being used for cross-site tracking by either blocking or partitioning them.
              
Unsupported
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: , , , , 

result, different session: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: , , , , 

result, different session: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: , , , , 

result, different session: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: , , , , 

result, different session: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: , , , , 

result, different session: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: , , , , 

result, different session: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: , , , , 

result, different session: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: , , , , 

result, different session: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: , , , , 

result, different session: , , , , 

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (secret) => {
      document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`;
    }

read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null

result, same session: null

result, different session: null

unsupported: true

passed: undefined

test failed: false
CookieStore
The Cookie Store API is an alternative asynchronous API for managing cookies, supported by some browsers.
              
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

result, different session: 
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported,
Error: Unsupported

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (data) => {
      const msPerHour = 60 * 60 * 1000;
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      window.cookieStore.set({
        name: "partition_test",
        value: data,
        expires: Date.now() + msPerHour,
        sameSite: "none"
      });
    }

read: async () => {
      if (!window.cookieStore) {
        throw new Error("Unsupported");
      }
      const cookie = await window.cookieStore.get("partition_test");
      if (!cookie) {
        return null;
      }
      return cookie.value;
    }

result, same session: Error: Unsupported

result, different session: Error: Unsupported

unsupported: true

passed: undefined

test failed: false
CSS cache
CSS stylesheets are cached, and if that cache is shared between websites, it can be used to track users across sites.
              
Failed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: 
fake_5840679953561614,
fake_35413440393642137,
fake_11476148347195392,
fake_49072913386115036,
fake_9984645066303313

result, different session: 
fake_5840679953561614,
fake_35413440393642137,
fake_11476148347195392,
fake_49072913386115036,
fake_9984645066303313

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: 
fake_3835059856509728,
fake_6435855307338656,
fake_085080083160044,
fake_34914511612391674,
fake_18085396342295335

result, different session: 
fake_3835059856509728,
fake_6435855307338656,
fake_085080083160044,
fake_34914511612391674,
fake_18085396342295335

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: 
fake_24600889323748576,
fake_5293856141385067,
fake_6450645909887789,
fake_8589971523971678,
fake_3334999443786768

result, different session: 
fake_24600889323748576,
fake_5293856141385067,
fake_6450645909887789,
fake_8589971523971678,
fake_3334999443786768

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: 
fake_4217105696650716,
fake_9582376806188833,
fake_5455313393144212,
fake_6549225945324761,
fake_0711239442901197

result, different session: 
fake_4217105696650716,
fake_9582376806188833,
fake_5455313393144212,
fake_6549225945324761,
fake_0711239442901197

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: 
fake_5805439118368734,
fake_5494240039695142,
fake_8153135944281915,
fake_25159938359745815,
fake_38787451843959153

result, different session: 
fake_5805439118368734,
fake_5494240039695142,
fake_8153135944281915,
fake_25159938359745815,
fake_38787451843959153

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: 
fake_42768915018105114,
fake_27806003594639517,
fake_9723486357535729,
fake_7635275059745423,
fake_16395726090358242

result, different session: 
fake_42591006360242045,
fake_3269289358227885,
fake_11492800623793453,
fake_7111501526568604,
fake_23089625443535677

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: 
fake_5665352078169501,
fake_5898673839082356,
fake_43828679006050963,
fake_5888806705345013,
fake_3300250816585639

result, different session: 
fake_5665352078169501,
fake_5898673839082356,
fake_43828679006050963,
fake_5888806705345013,
fake_3300250816585639

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: 
fake_2628738413214089,
fake_7506352102558782,
fake_8552521644582103,
fake_5258374680597053,
fake_4579335411669554

result, different session: 
fake_8754201265815726,
fake_39996886679680976,
fake_7698036021081753,
fake_34389355259605003,
fake_5186960988813274

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: 
fake_8842340553045138,
fake_9708162639974127,
fake_7368858918050254,
fake_5720914224325191,
fake_7720281237062367

result, different session: 
fake_8842340553045138,
fake_9708162639974127,
fake_7368858918050254,
fake_5720914224325191,
fake_7720281237062367

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return key;
    }

read: async (key) => {
      const href = testURI("resource", "css", key);
      const head = document.getElementsByTagName("head")[0];
      head.innerHTML += `<link type="text/css" rel="stylesheet" href="${href}">`;
      const testElement = document.querySelector("#css");
      let fontFamily;
      while (true) {
        await sleepMs(100);
        fontFamily = getComputedStyle(testElement).fontFamily;
        if (fontFamily.startsWith("fake")) {
          break;
        }
      }
      console.log(fontFamily);
      return fontFamily;
    }

result, same session: fake_19258678993749911

result, different session: fake_5900754315998238

unsupported: false

passed: true

test failed: false
favicon cache
A favicon is an icon that represents a website, typically shown in browser tab and bookmarks menu. If the favicon cache is not partitioned, it can be used to track users across websites.
              
Failed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Unsupported
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Failed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Unsupported
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Failed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 2, 2, 2, 1, 1

result, different session: 2, 2, 2, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => key

read: async (key) => {
      // Wait for the favicon to load (defined in supercookies.html)
      await sleepMs(2000);
      let response = await fetch(
        testURI("ctr", "favicon", key), {"cache": "reload"});
      let count = (await response.text()).trim();
      if (count === "0") {
        throw new Error("No requests received");
      }
      return count;
    }

result, same session: 1

result, different session: 1

unsupported: false

passed: false

test failed: false
fetch cache
When a resource is received via the Fetch API, it is frequently cached. That cache can potentially be abused for cross-site tracking.
              
Failed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 2, 2, 2, 2, 2

result, different session: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 2, 2, 2, 2, 2

result, different session: 3, 3, 3, 3, 3

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      return key;
    }

read: async (key) => {
      let response = await fetch(testURI("resource", "fetch", key),
                                 {cache: "force-cache"});
      let countResponse = await fetch(testURI("ctr", "fetch", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1

result, different session: 2

unsupported: false

passed: true

test failed: false
font cache
Web fonts are sometimes stored in their own cache, which is vulnerable to being abused for cross-site tracking.
              
Failed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } body { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      return key;
    }

read: async (key) => {
      const text = document.createElement("span");
      text.id = "text";
      text.innerText = "test";
      document.body.appendChild(text);
      const originalWidth = text.getBoundingClientRect().width;
      let style = document.createElement("style");
      style.type='text/css';
      let fontURI = testURI("resource", "font", key);
      style.innerHTML = `@font-face {font-family: "myFont"; src: url("${fontURI}"); } #text { font-family: "myFont" }`;
      document.getElementsByTagName("head")[0].appendChild(style);
      let newWidth;
      do {
        await sleepMs(100);
        newWidth = text.getBoundingClientRect().width;
      } while (newWidth < 0 || newWidth === originalWidth)
      let response = await fetch(
        testURI("ctr", "font", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1

result, different session: 2

unsupported: false

passed: true

test failed: false
iframe cache
An iframe is an element in a web page than allows websites to embed a second web page. Caching of this web page could be abused for cross-site tracking.
              
Failed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      iframe.addEventListener("load", () => resolve(key), {once: true});
      iframe.src = testURI("resource", "page", key);
    })

read: async (key) => {
      let iframe = document.createElement("iframe");
      document.body.appendChild(iframe);
      let iframeLoadPromise = new Promise((resolve, reject) => {
        iframe.addEventListener("load", resolve, {once: true});
      });
      let address = testURI("resource", "page", key);
      iframe.src = address;
      await iframeLoadPromise;
      let response = await fetch(
        testURI("ctr", "page", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1

result, different session: 2

unsupported: false

passed: true

test failed: false
image cache
Caching of images in web browsers is a standard behavior. But if that cache leaks between websites, it can be abused for cross-site tracking.
              
Failed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      img.addEventListener("load", () => resolve(key), {once: true});
      img.src = testURI("resource", "image", key);
    })

read: async (key) => {
      let img = document.createElement("img");
      document.body.appendChild(img);
      let imgLoadPromise = new Promise((resolve, reject) => {
        img.addEventListener("load", resolve, {once: true});
      });
      img.src = testURI("resource", "image", key);
      await imgLoadPromise;
      let response = await fetch(
        testURI("ctr", "image", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1

result, different session: 2

unsupported: false

passed: true

test failed: false
indexedDB
The IndexedDB API exposes a transactional database to web pages. That database can be used to track users across websites, unless it is partitioned.
              
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 
4bde1512-0784-43fb-887a-56a509216ec5_3p,
41005147-8107-4a0f-bd00-5de04892fc40_3p,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1_3p,
bcde0d87-19c8-4d11-b69d-cf5b05adac32_3p,
cf7b9801-6b0c-4efc-9361-c923491dbafc_3p

result, different session: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 
6ff0b878-e459-4077-873d-c4d73a8b4c3f_3p,
94d0ff49-2e50-4f68-a576-2f481a9b0dfb_3p,
db9ededa-3d85-49d1-b22f-66b9d13151e9_3p,
eda356c0-dfbb-48c4-98bc-e3060f20796d_3p,
45855e06-c12b-4c97-a80f-b05d0634705e_3p

result, different session: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 
58109673-6b30-4c3c-93dc-9f3935edeced_3p,
2aa2bf6f-0a07-4a35-ae45-e9b6a1d11e20_3p,
732a589c-ffa1-441f-b046-e96ae5ecce3b_3p,
be322cbd-9046-492a-8283-325c7e6e36ca_3p,
4d80e8ed-2942-4e43-80e6-7e11a7e16883_3p

result, different session: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 
9f1a20c0-3f9c-4aa5-8aa8-e56950e57e74_3p,
e4fef07d-00dc-4960-8421-eaed44851eed_3p,
154af211-304d-45c2-bd1d-edfcf6a953c2_3p,
bbc94382-8354-43fa-9caa-06c72e77a772_3p,
5cd2be12-be84-4ee2-ad4f-e8bd13d52186_3p

result, different session: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 
a09b69c9-0216-4504-9061-fc5c61dd3c23_3p,
7b6315a4-06ef-4ac0-8f42-ce400041b707_3p,
2d5c9ed0-3dbd-48e7-84ef-eb6e8484cdbf_3p,
65902525-09ad-4c46-865a-d3fc1f63ac7b_3p,
6e3bb471-c66f-4f24-8437-1dbee8645c0e_3p

result, different session: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 
c4e8c0f1-6882-4a88-b2b0-1abda72db45e_3p,
ae52c0dc-9b2c-4efd-9348-d816b188d956_3p,
9d44a7cf-1964-4a73-81b3-b7941a1a8e4d_3p,
3a9a3eda-7e51-42b7-9ccf-5557bf5b9c77_3p,
896b9c56-96e4-44cb-9a3b-76bd875cead7_3p

result, different session: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 
213faa81-9820-4e64-8ca2-4b2c56e0fd16_3p,
cf7391f7-aa80-401f-81c4-7c2508844631_3p,
6cb5025c-2699-446a-9372-39087b296a21_3p,
9a0e433f-dc60-4ba4-ba79-fa1ff3caccb5_3p,
4335c2dd-8867-446f-8184-bd81aa0654b6_3p

result, different session: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 
1e854cf6-6d0d-4987-b89f-4f0e6bfb3013_3p,
2485a3ce-aa3e-4197-ba4a-2835da79e7ac_3p,
f8e56e03-da27-4aae-9eee-18c4b864da6a_3p,
63fc99e9-1362-4918-9b98-fd62c233cfaf_3p,
7fe7e385-59f1-4ded-a894-f9710f27446e_3p

result, different session: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 
b4e6c154-78d4-4ea8-9de8-7342f2b90461_3p,
a938646f-4e8a-409b-8a23-9aa66b47e388_3p,
26e63861-906d-420b-bba7-f80b45898c34_3p,
cda34f43-1255-481b-9e0d-1c216b86d6fa_3p,
6779afe3-026e-4315-87e0-9c8f43f3c72c_3p

result, different session: undefined

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: async (secret) => {
      try {
        return await IdbKeyVal.set("secret", secret);
      } catch (e) {
        throw new Error("Unsupported");
      }
    }

read: () => IdbKeyVal.get("secret")

result, same session: 40268717-416c-4353-9311-83b6625eb429_3p

result, different session: undefined

unsupported: false

passed: true

test failed: false
localStorage
The localStorage API gives websites access to a key-value database that will remain available across visits. If the localStorage API is not partitioned or blocked, it can also be used to track users across websites.
              
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 
4bde1512-0784-43fb-887a-56a509216ec5_3p,
41005147-8107-4a0f-bd00-5de04892fc40_3p,
f7f9cc07-d4e3-4814-b5c4-3dcf2c2543d1_3p,
bcde0d87-19c8-4d11-b69d-cf5b05adac32_3p,
cf7b9801-6b0c-4efc-9361-c923491dbafc_3p

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 
6ff0b878-e459-4077-873d-c4d73a8b4c3f_3p,
94d0ff49-2e50-4f68-a576-2f481a9b0dfb_3p,
db9ededa-3d85-49d1-b22f-66b9d13151e9_3p,
eda356c0-dfbb-48c4-98bc-e3060f20796d_3p,
45855e06-c12b-4c97-a80f-b05d0634705e_3p

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 
58109673-6b30-4c3c-93dc-9f3935edeced_3p,
2aa2bf6f-0a07-4a35-ae45-e9b6a1d11e20_3p,
732a589c-ffa1-441f-b046-e96ae5ecce3b_3p,
be322cbd-9046-492a-8283-325c7e6e36ca_3p,
4d80e8ed-2942-4e43-80e6-7e11a7e16883_3p

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 
9f1a20c0-3f9c-4aa5-8aa8-e56950e57e74_3p,
e4fef07d-00dc-4960-8421-eaed44851eed_3p,
154af211-304d-45c2-bd1d-edfcf6a953c2_3p,
bbc94382-8354-43fa-9caa-06c72e77a772_3p,
5cd2be12-be84-4ee2-ad4f-e8bd13d52186_3p

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 
a09b69c9-0216-4504-9061-fc5c61dd3c23_3p,
7b6315a4-06ef-4ac0-8f42-ce400041b707_3p,
2d5c9ed0-3dbd-48e7-84ef-eb6e8484cdbf_3p,
65902525-09ad-4c46-865a-d3fc1f63ac7b_3p,
6e3bb471-c66f-4f24-8437-1dbee8645c0e_3p

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 
c4e8c0f1-6882-4a88-b2b0-1abda72db45e_3p,
ae52c0dc-9b2c-4efd-9348-d816b188d956_3p,
9d44a7cf-1964-4a73-81b3-b7941a1a8e4d_3p,
3a9a3eda-7e51-42b7-9ccf-5557bf5b9c77_3p,
896b9c56-96e4-44cb-9a3b-76bd875cead7_3p

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 
213faa81-9820-4e64-8ca2-4b2c56e0fd16_3p,
cf7391f7-aa80-401f-81c4-7c2508844631_3p,
6cb5025c-2699-446a-9372-39087b296a21_3p,
9a0e433f-dc60-4ba4-ba79-fa1ff3caccb5_3p,
4335c2dd-8867-446f-8184-bd81aa0654b6_3p

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 
1e854cf6-6d0d-4987-b89f-4f0e6bfb3013_3p,
2485a3ce-aa3e-4197-ba4a-2835da79e7ac_3p,
f8e56e03-da27-4aae-9eee-18c4b864da6a_3p,
63fc99e9-1362-4918-9b98-fd62c233cfaf_3p,
7fe7e385-59f1-4ded-a894-f9710f27446e_3p

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 
b4e6c154-78d4-4ea8-9de8-7342f2b90461_3p,
a938646f-4e8a-409b-8a23-9aa66b47e388_3p,
26e63861-906d-420b-bba7-f80b45898c34_3p,
cda34f43-1255-481b-9e0d-1c216b86d6fa_3p,
6779afe3-026e-4315-87e0-9c8f43f3c72c_3p

result, different session: , , , , 

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Passed
write: (secret) => localStorage.setItem("secret", secret)

read: () => localStorage.getItem("secret")

result, same session: 40268717-416c-4353-9311-83b6625eb429_3p

result, different session: null

unsupported: false

passed: true

test failed: false
prefetch cache
A <link rel='prefetch'...> suggests to browsers they should fetch a resource ahead of time and cache it. But if browsers don't partition this cache, it can be used to track users across websites.
              
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

result, different session: 
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received,
Error: No requests received

unsupported: true, true, true, true, true

passed: undefined

test failed: false, false, false, false, false
Unsupported
write: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      return key;
    }

read: async (key) => {
      let link = document.createElement("link");
      link.rel = "prefetch";
      link.href = testURI("resource", "prefetch", key);
      document.getElementsByTagName("head")[0].appendChild(link);
      await sleepMs(500);
      let response = await fetch(
        testURI("ctr", "prefetch", key), {"cache": "reload"});
      let countString = (await response.text()).trim();
      if (parseInt(countString) === 0) {
        throw new Error("No requests received");
      }
      return countString;
    }

result, same session: Error: No requests received

result, different session: Error: No requests received

unsupported: true

passed: undefined

test failed: false
script cache
Caching of scripts in web browsers is a standard behavior. But if that cache leaks between websites, it can be abused for cross-site tracking.
              
Failed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: (key) => new Promise((resolve, reject) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      script.addEventListener("load", () => resolve(key), {once: true});
      script.src = testURI("resource", "script", key);
    })

read: async (key) => {
      let script = document.createElement("script");
      document.body.appendChild(script);
      let scriptLoadPromise = new Promise((resolve, reject) => {
        script.addEventListener("load", resolve, {once: true});
      });
      script.src = testURI("resource", "script", key);
      await scriptLoadPromise;
      let response = await fetch(
        testURI("ctr", "script", key), {"cache": "reload"});
      return (await response.text()).trim();
    }

result, same session: 1

result, different session: 2

unsupported: false

passed: true

test failed: false
XMLHttpRequest cache
Similar to the newer Fetch API, any resource received may be cached by the browser. The cache is potentially vulnerable to cross-site tracking attack.
              
Failed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 2, 2, 2, 2, 2

unsupported: false, false, false, false, false

passed: true, true, true, true, true

test failed: false, false, false, false, false
Failed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1, 1, 1, 1, 1

result, different session: 1, 1, 1, 1, 1

unsupported: false, false, false, false, false

passed: false, false, false, false, false

test failed: false, false, false, false, false
Passed
write: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      return key;
    }

read: async (key) => {
      const req = new XMLHttpRequest();
      const loadPromise = new Promise(resolve => req.addEventListener("load", resolve));
      req.open("GET", testURI("resource", "xhr", key));
      req.send();
      await loadPromise;
      let countResponse = await fetch(testURI("ctr", "xhr", key),
                                      {cache: "reload"});
      return (await countResponse.text()).trim();
    }

result, same session: 1

result, different session: 2

unsupported: false

passed: true

test failed: false