Desktop private modes

(default settings)

brave
1.58

private

chrome
116.0

private

edge
117.0

private

firefox
117.0

private

librewolf
117.0

private

mullvad
12.5

private

opera
102.0

private

safari
16.6

private

tor
12.5

private

ungoogled
116.0

private

vivaldi
6.2

private
State Partitioning tests Which 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-SvcAlt-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.
  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: h3, h3, h3 result, different first party: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: h3, h3, h3 result, different first party: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: h3, h3, h3 result, different first party: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: h3, h3, h3 result, different first party: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: h3, h3, h3 result, different first party: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: h3, h3, h3 result, different first party: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: h3, h3, h3 result, different first party: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
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, h2, h2, h2, h2 unsupported: true, true, true, true, true passed: undefined test failed: false, false, false, false, false
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 result, different first party: h2, h2, h2 unsupported: true, true, true passed: undefined test failed: false, false, false
  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: h3, h3, h3 result, different first party: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: h3, h3, h3 result, different first party: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
blobA 'blob URL' is a local reference to some raw data. Trackers can use a blob URL to share data between websites.
  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=${secret}`); let result = await response.json(); let blobUrl = decodeURIComponent(result.blobUrl); let blobResponse = await fetch(blobUrl); return blobResponse.text(); } result, same first party: 5465a603-de27-44f5-b8c4-707bfb613e2e, 78421fc4-bf96-4cca-890a-80da7897dc6d, 80b14108-7165-4df7-a9e6-ff02143416a6 result, different first party: Error: Failed to fetch, Error: Failed to fetch, Error: Failed to fetch unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { try { let blobURL = URL.createObjectURL(new Blob([secret])); fetch(`${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: 716abdfe-395d-427a-95f5-86b590a83dbe, 74b40c1c-a56c-422c-8ec2-977bc24c84e1, a1abfa62-2197-4ef7-a6aa-1649c66a9829 result, different first party: 716abdfe-395d-427a-95f5-86b590a83dbe, 74b40c1c-a56c-422c-8ec2-977bc24c84e1, a1abfa62-2197-4ef7-a6aa-1649c66a9829 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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=${secret}`); let result = await response.json(); let blobUrl = decodeURIComponent(result.blobUrl); let blobResponse = await fetch(blobUrl); return blobResponse.text(); } result, same first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 result, different first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  write: (secret) => { try { let blobURL = URL.createObjectURL(new Blob([secret])); fetch(`${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: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826, cf35c52d-e97f-4820-82eb-d8054844f2c1 result, different first party: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826, cf35c52d-e97f-4820-82eb-d8054844f2c1 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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=${secret}`); let result = await response.json(); let blobUrl = decodeURIComponent(result.blobUrl); let blobResponse = await fetch(blobUrl); return blobResponse.text(); } result, same first party: e37747b4-8740-49ba-9270-601151aaf726, e2e870e7-134c-4209-b335-78130b0eb740, af1f42ee-1067-499d-8093-d4d19b5c49a6 result, different first party: e37747b4-8740-49ba-9270-601151aaf726, e2e870e7-134c-4209-b335-78130b0eb740, af1f42ee-1067-499d-8093-d4d19b5c49a6 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  write: (secret) => { try { let blobURL = URL.createObjectURL(new Blob([secret])); fetch(`${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: b71a2d50-2167-4614-a844-3de0e93814fb, 87735b1f-b9af-4abe-8b23-8eb0096d3907, e9f1e434-9ee8-4cdb-b17e-75370f35bfa9 result, different first party: Error: NetworkError when attempting to fetch resource., Error: NetworkError when attempting to fetch resource., Error: NetworkError when attempting to fetch resource. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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=${secret}`); let result = await response.json(); let blobUrl = decodeURIComponent(result.blobUrl); let blobResponse = await fetch(blobUrl); return blobResponse.text(); } result, same first party: c28bfb99-bfe7-484e-91ee-401936368f8e, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6, 41f02047-71ab-44db-a34c-341407f5d677 result, different first party: c28bfb99-bfe7-484e-91ee-401936368f8e, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6, 41f02047-71ab-44db-a34c-341407f5d677 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  write: (secret) => { try { let blobURL = URL.createObjectURL(new Blob([secret])); fetch(`${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: c24314e8-1afc-4d9a-96a4-bc75e5d99b58, aa3c8308-259e-464e-aa4f-6e3b827d137c, 358e00ee-1af1-443e-8d23-1fa8923e03fc, 7fe8a160-092e-4a52-81cd-841a2600cf16, cafc6b09-49db-407e-950e-bab9a6e60e9f result, different first party: c24314e8-1afc-4d9a-96a4-bc75e5d99b58, aa3c8308-259e-464e-aa4f-6e3b827d137c, 358e00ee-1af1-443e-8d23-1fa8923e03fc, 7fe8a160-092e-4a52-81cd-841a2600cf16, cafc6b09-49db-407e-950e-bab9a6e60e9f unsupported: false, false, false, false, false passed: false, false, false, false, false test failed: false, false, false, false, false
  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=${secret}`); let result = await response.json(); let blobUrl = decodeURIComponent(result.blobUrl); let blobResponse = await fetch(blobUrl); return blobResponse.text(); } result, same first party: 91977509-fee5-471e-9ccb-9dd38fc58a67, aab3ddfd-726f-4857-83c6-8d44ea5e6bb4, 43c85c36-872d-485b-852e-5b322a7c7d45 result, different first party: Error: NetworkError when attempting to fetch resource., Error: NetworkError when attempting to fetch resource., Error: NetworkError when attempting to fetch resource. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { try { let blobURL = URL.createObjectURL(new Blob([secret])); fetch(`${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: 48c217f0-1bef-4ff9-a86a-e02c452b3090, 52225fb2-48b7-4a6d-8cba-f85356406aba, 5616596f-2317-42fc-bd3f-f8e6bc122d3e result, different first party: 48c217f0-1bef-4ff9-a86a-e02c452b3090, 52225fb2-48b7-4a6d-8cba-f85356406aba, 5616596f-2317-42fc-bd3f-f8e6bc122d3e unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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: a5be31f4-aa0a-4843-923b-3c4f83f5a928, e31de4a2-0c0c-4125-b3cc-46d11e5579f9, 8db17cd7-36fc-475c-8d65-e14f8da75dc6 result, different first party: a5be31f4-aa0a-4843-923b-3c4f83f5a928, e31de4a2-0c0c-4125-b3cc-46d11e5579f9, 8db17cd7-36fc-475c-8d65-e14f8da75dc6 unsupported: false, false, false passed: false, false, false test failed: false, false, false
BroadcastChannelA BroadcastChannel is designed to send messages between tabs. In some browsers it can be used for cross-site communication and tracking.
  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: 5465a603-de27-44f5-b8c4-707bfb613e2e, 78421fc4-bf96-4cca-890a-80da7897dc6d, 80b14108-7165-4df7-a9e6-ff02143416a6 result, different first party: Error: no BroadcastChannel message, Error: no BroadcastChannel message, Error: no BroadcastChannel message unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 716abdfe-395d-427a-95f5-86b590a83dbe, 74b40c1c-a56c-422c-8ec2-977bc24c84e1, a1abfa62-2197-4ef7-a6aa-1649c66a9829 result, different first party: 716abdfe-395d-427a-95f5-86b590a83dbe, 74b40c1c-a56c-422c-8ec2-977bc24c84e1, a1abfa62-2197-4ef7-a6aa-1649c66a9829 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 result, different first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826, cf35c52d-e97f-4820-82eb-d8054844f2c1 result, different first party: Error: no BroadcastChannel message, Error: no BroadcastChannel message, Error: no BroadcastChannel message unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: e37747b4-8740-49ba-9270-601151aaf726, e2e870e7-134c-4209-b335-78130b0eb740, af1f42ee-1067-499d-8093-d4d19b5c49a6 result, different first party: Error: no BroadcastChannel message, Error: no BroadcastChannel message, Error: no BroadcastChannel message unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: b71a2d50-2167-4614-a844-3de0e93814fb, 87735b1f-b9af-4abe-8b23-8eb0096d3907, e9f1e434-9ee8-4cdb-b17e-75370f35bfa9 result, different first party: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: c28bfb99-bfe7-484e-91ee-401936368f8e, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6, 41f02047-71ab-44db-a34c-341407f5d677 result, different first party: c28bfb99-bfe7-484e-91ee-401936368f8e, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6, 41f02047-71ab-44db-a34c-341407f5d677 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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: c24314e8-1afc-4d9a-96a4-bc75e5d99b58, aa3c8308-259e-464e-aa4f-6e3b827d137c, 358e00ee-1af1-443e-8d23-1fa8923e03fc, 7fe8a160-092e-4a52-81cd-841a2600cf16, cafc6b09-49db-407e-950e-bab9a6e60e9f 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: true, true, true, true, true test failed: false, false, false, false, false
  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: 91977509-fee5-471e-9ccb-9dd38fc58a67, aab3ddfd-726f-4857-83c6-8d44ea5e6bb4, 43c85c36-872d-485b-852e-5b322a7c7d45 result, different first party: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 48c217f0-1bef-4ff9-a86a-e02c452b3090, 52225fb2-48b7-4a6d-8cba-f85356406aba, 5616596f-2317-42fc-bd3f-f8e6bc122d3e result, different first party: 48c217f0-1bef-4ff9-a86a-e02c452b3090, 52225fb2-48b7-4a6d-8cba-f85356406aba, 5616596f-2317-42fc-bd3f-f8e6bc122d3e unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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: a5be31f4-aa0a-4843-923b-3c4f83f5a928, e31de4a2-0c0c-4125-b3cc-46d11e5579f9, 8db17cd7-36fc-475c-8d65-e14f8da75dc6 result, different first party: a5be31f4-aa0a-4843-923b-3c4f83f5a928, e31de4a2-0c0c-4125-b3cc-46d11e5579f9, 8db17cd7-36fc-475c-8d65-e14f8da75dc6 unsupported: false, false, false passed: false, false, false test failed: false, false, false
CacheStorageThe 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.
  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: 5465a603-de27-44f5-b8c4-707bfb613e2e, 78421fc4-bf96-4cca-890a-80da7897dc6d, 80b14108-7165-4df7-a9e6-ff02143416a6 result, different first party: Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${key}`]); } catch (e) { throw new Error("Unsupported"); } } read: async () => { let cache = await caches.open("supercookies"); let cacheKeys = await cache.keys(); let url = cacheKeys[0].url; return (new URL(url)).searchParams.get("key"); } result, same first party: 716abdfe-395d-427a-95f5-86b590a83dbe, 74b40c1c-a56c-422c-8ec2-977bc24c84e1, a1abfa62-2197-4ef7-a6aa-1649c66a9829 result, different first party: Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${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: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 result, different first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 unsupported: false, false, false passed: false, false, false test failed: false, false, false
write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${key}`]); } catch (e) { throw new Error("Unsupported"); } } read: async () => { let cache = await caches.open("supercookies"); let cacheKeys = await cache.keys(); let url = cacheKeys[0].url; return (new URL(url)).searchParams.get("key"); } result, same first party: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. result, different first party: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${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: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. result, different first party: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${key}`]); } catch (e) { throw new Error("Unsupported"); } } read: async () => { let cache = await caches.open("supercookies"); let cacheKeys = await cache.keys(); let url = cacheKeys[0].url; return (new URL(url)).searchParams.get("key"); } result, same first party: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. result, different first party: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: true, true, true passed: undefined test failed: false, false, false
  write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${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: c28bfb99-bfe7-484e-91ee-401936368f8e, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6, 41f02047-71ab-44db-a34c-341407f5d677 result, different first party: Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${key}`]); } catch (e) { throw new Error("Unsupported"); } } read: async () => { let cache = await caches.open("supercookies"); let cacheKeys = await cache.keys(); let url = cacheKeys[0].url; return (new URL(url)).searchParams.get("key"); } result, same first party: c24314e8-1afc-4d9a-96a4-bc75e5d99b58, aa3c8308-259e-464e-aa4f-6e3b827d137c, 358e00ee-1af1-443e-8d23-1fa8923e03fc, 7fe8a160-092e-4a52-81cd-841a2600cf16, cafc6b09-49db-407e-950e-bab9a6e60e9f result, different first party: Error: undefined is not an object (evaluating 'cacheKeys[0].url'), Error: undefined is not an object (evaluating 'cacheKeys[0].url'), Error: undefined is not an object (evaluating 'cacheKeys[0].url'), Error: undefined is not an object (evaluating 'cacheKeys[0].url'), Error: undefined is not an object (evaluating 'cacheKeys[0].url') unsupported: false, false, false, false, false passed: true, true, true, true, true test failed: false, false, false, false, false
write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${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: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. result, different first party: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: true, true, true passed: undefined test failed: false, false, false
  write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${key}`]); } catch (e) { throw new Error("Unsupported"); } } read: async () => { let cache = await caches.open("supercookies"); let cacheKeys = await cache.keys(); let url = cacheKeys[0].url; return (new URL(url)).searchParams.get("key"); } result, same first party: 48c217f0-1bef-4ff9-a86a-e02c452b3090, 52225fb2-48b7-4a6d-8cba-f85356406aba, 5616596f-2317-42fc-bd3f-f8e6bc122d3e result, different first party: Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${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: a5be31f4-aa0a-4843-923b-3c4f83f5a928, e31de4a2-0c0c-4125-b3cc-46d11e5579f9, 8db17cd7-36fc-475c-8d65-e14f8da75dc6 result, different first party: Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent. unsupported: false, false, false passed: true, true, true test failed: false, false, 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.
  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(`${baseURI}headers`); let cookie = (await response.json())["cookie"]; return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null; } result, same first party: 5465a603-de27-44f5-b8c4-707bfb613e2e_http, 78421fc4-bf96-4cca-890a-80da7897dc6d_http, 80b14108-7165-4df7-a9e6-ff02143416a6_http result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value. await fetch(`${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: 716abdfe-395d-427a-95f5-86b590a83dbe_http, 74b40c1c-a56c-422c-8ec2-977bc24c84e1_http, a1abfa62-2197-4ef7-a6aa-1649c66a9829_http result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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(`${baseURI}headers`); let cookie = (await response.json())["cookie"]; return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null; } result, same first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a_http, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51_http, 0e22765a-3b45-4d4f-96e1-155b36d72016_http result, different first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a_http, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51_http, 0e22765a-3b45-4d4f-96e1-155b36d72016_http unsupported: false, false, false passed: false, false, false test failed: false, false, false
  write: async (secret) => { // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value. await fetch(`${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: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4_http, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826_http, cf35c52d-e97f-4820-82eb-d8054844f2c1_http result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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(`${baseURI}headers`); let cookie = (await response.json())["cookie"]; return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null; } result, same first party: e37747b4-8740-49ba-9270-601151aaf726_http, e2e870e7-134c-4209-b335-78130b0eb740_http, af1f42ee-1067-499d-8093-d4d19b5c49a6_http result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value. await fetch(`${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: b71a2d50-2167-4614-a844-3de0e93814fb_http, 87735b1f-b9af-4abe-8b23-8eb0096d3907_http, e9f1e434-9ee8-4cdb-b17e-75370f35bfa9_http result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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(`${baseURI}headers`); let cookie = (await response.json())["cookie"]; return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null; } result, same first party: c28bfb99-bfe7-484e-91ee-401936368f8e_http, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6_http, 41f02047-71ab-44db-a34c-341407f5d677_http result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value. await fetch(`${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: c24314e8-1afc-4d9a-96a4-bc75e5d99b58_http, aa3c8308-259e-464e-aa4f-6e3b827d137c_http, 358e00ee-1af1-443e-8d23-1fa8923e03fc_http, 7fe8a160-092e-4a52-81cd-841a2600cf16_http, cafc6b09-49db-407e-950e-bab9a6e60e9f_http result, different first party: , , , , unsupported: false, false, false, false, false passed: true, true, true, true, true test failed: false, false, false, false, false
  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(`${baseURI}headers`); let cookie = (await response.json())["cookie"]; return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null; } result, same first party: 91977509-fee5-471e-9ccb-9dd38fc58a67_http, aab3ddfd-726f-4857-83c6-8d44ea5e6bb4_http, 43c85c36-872d-485b-852e-5b322a7c7d45_http result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value. await fetch(`${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: 48c217f0-1bef-4ff9-a86a-e02c452b3090_http, 52225fb2-48b7-4a6d-8cba-f85356406aba_http, 5616596f-2317-42fc-bd3f-f8e6bc122d3e_http result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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(`${baseURI}headers`); let cookie = (await response.json())["cookie"]; return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null; } result, same first party: a5be31f4-aa0a-4843-923b-3c4f83f5a928_http, e31de4a2-0c0c-4125-b3cc-46d11e5579f9_http, 8db17cd7-36fc-475c-8d65-e14f8da75dc6_http result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
cookie (JS)The cookie, first introduced by Netscape in 1994, is a small amount of data stored by your browser on a website's behalf. It has legitimate uses, but it is also the classic cross-site tracking mechanism, and today still the most popular method of tracking users across websites. Browsers can stop cookies from being used for cross-site tracking by either blocking or partitioning them.
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same first party: 5465a603-de27-44f5-b8c4-707bfb613e2e_js, 78421fc4-bf96-4cca-890a-80da7897dc6d_js, 80b14108-7165-4df7-a9e6-ff02143416a6_js result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same first party: 716abdfe-395d-427a-95f5-86b590a83dbe_js, 74b40c1c-a56c-422c-8ec2-977bc24c84e1_js, a1abfa62-2197-4ef7-a6aa-1649c66a9829_js result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a_js, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51_js, 0e22765a-3b45-4d4f-96e1-155b36d72016_js result, different first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a_js, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51_js, 0e22765a-3b45-4d4f-96e1-155b36d72016_js unsupported: false, false, false passed: false, false, false test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same first party: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4_js, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826_js, cf35c52d-e97f-4820-82eb-d8054844f2c1_js result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same first party: e37747b4-8740-49ba-9270-601151aaf726_js, e2e870e7-134c-4209-b335-78130b0eb740_js, af1f42ee-1067-499d-8093-d4d19b5c49a6_js result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same first party: b71a2d50-2167-4614-a844-3de0e93814fb_js, 87735b1f-b9af-4abe-8b23-8eb0096d3907_js, e9f1e434-9ee8-4cdb-b17e-75370f35bfa9_js result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same first party: c28bfb99-bfe7-484e-91ee-401936368f8e_js, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6_js, 41f02047-71ab-44db-a34c-341407f5d677_js result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same first party: c24314e8-1afc-4d9a-96a4-bc75e5d99b58_js, aa3c8308-259e-464e-aa4f-6e3b827d137c_js, 358e00ee-1af1-443e-8d23-1fa8923e03fc_js, 7fe8a160-092e-4a52-81cd-841a2600cf16_js, cafc6b09-49db-407e-950e-bab9a6e60e9f_js result, different first party: , , , , unsupported: false, false, false, false, false passed: true, true, true, true, true test failed: false, false, false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same first party: 91977509-fee5-471e-9ccb-9dd38fc58a67_js, aab3ddfd-726f-4857-83c6-8d44ea5e6bb4_js, 43c85c36-872d-485b-852e-5b322a7c7d45_js result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same first party: 48c217f0-1bef-4ff9-a86a-e02c452b3090_js, 52225fb2-48b7-4a6d-8cba-f85356406aba_js, 5616596f-2317-42fc-bd3f-f8e6bc122d3e_js result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same first party: a5be31f4-aa0a-4843-923b-3c4f83f5a928_js, e31de4a2-0c0c-4125-b3cc-46d11e5579f9_js, 8db17cd7-36fc-475c-8d65-e14f8da75dc6_js result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
CookieStoreThe Cookie Store API is an alternative asynchronous API for managing cookies, supported by some browsers.
  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: 5465a603-de27-44f5-b8c4-707bfb613e2e, 78421fc4-bf96-4cca-890a-80da7897dc6d, 80b14108-7165-4df7-a9e6-ff02143416a6 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 716abdfe-395d-427a-95f5-86b590a83dbe, 74b40c1c-a56c-422c-8ec2-977bc24c84e1, a1abfa62-2197-4ef7-a6aa-1649c66a9829 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 result, different first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 unsupported: false, false, false passed: false, false, false test failed: false, false, false
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 result, different first party: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: true, true, true passed: undefined test failed: false, false, false
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 result, different first party: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: true, true, true passed: undefined test failed: false, false, false
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 result, different first party: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: true, true, true passed: undefined test failed: false, false, false
  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: c28bfb99-bfe7-484e-91ee-401936368f8e, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6, 41f02047-71ab-44db-a34c-341407f5d677 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
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
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 result, different first party: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: true, true, true passed: undefined test failed: false, false, false
  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: 48c217f0-1bef-4ff9-a86a-e02c452b3090, 52225fb2-48b7-4a6d-8cba-f85356406aba, 5616596f-2317-42fc-bd3f-f8e6bc122d3e result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: a5be31f4-aa0a-4843-923b-3c4f83f5a928, e31de4a2-0c0c-4125-b3cc-46d11e5579f9, 8db17cd7-36fc-475c-8d65-e14f8da75dc6 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
CSS cacheCSS stylesheets are cached, and if that cache is shared between websites, it can be used to track users across sites.
  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_9967359656888628, fake_7193198019751421, fake_7056175277638146 result, different first party: fake_465807436842375, fake_1485194176940008, fake_5435033492875516 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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_875360429086746, fake_0798405836113516, fake_3430308829965676 result, different first party: fake_875360429086746, fake_0798405836113516, fake_3430308829965676 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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_37054844800942677, fake_5659488708500369, fake_26225814159788974 result, different first party: fake_37054844800942677, fake_5659488708500369, fake_26225814159788974 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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_8272292432434922, fake_9989979388184576, fake_89124961156331 result, different first party: fake_2990630728660877, fake_988957495819593, fake_2281190247969973 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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_4596124146001128, fake_9950191431461679, fake_49612049157878135 result, different first party: fake_49208348963134485, fake_7510515535643436, fake_8037475273406236 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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_9693854020894761, fake_4043366837644484, fake_5965714148071948 result, different first party: fake_07104487232522794, fake_954410645723806, fake_7146748615472986 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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_2653607340640769, fake_7395489391300523, fake_9376840120134962 result, different first party: fake_2653607340640769, fake_7395489391300523, fake_9376840120134962 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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_18227302067632078, fake_41541013572801866, fake_1265311640952289, fake_10144310396161527, fake_3638473169798595 result, different first party: fake_16375800140584817, fake_9698391245544093, fake_6419145359620666, fake_8964629042009518, fake_22449679420519986 unsupported: false, false, false, false, false passed: true, true, true, true, true test failed: false, false, false, false, false
  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_8622476974499826, fake_0414582988970551, fake_21716482720166996 result, different first party: fake_35037738783127037, fake_29801211882604006, fake_4156820670089454 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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_9630197312068272, fake_41451995685313237, fake_6799187048133744 result, different first party: fake_9630197312068272, fake_41451995685313237, fake_6799187048133744 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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_9151415409090569, fake_030447305808249725, fake_5710759516136283 result, different first party: fake_9151415409090569, fake_030447305808249725, fake_5710759516136283 unsupported: false, false, false passed: false, false, false test failed: false, false, false
favicon cacheA 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.
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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, 2 result, different first party: 3, 3, 3 unsupported: false, false, false passed: true, true, true test failed: false, false, false
fetch cacheWhen a resource is received via the Fetch API, it is frequently cached. That cache can potentially be abused for cross-site tracking.
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
font cacheWeb fonts are sometimes stored in their own cache, which is vulnerable to being abused for cross-site tracking.
  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: 1, 1, 1 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different first party: 1, 1, 1 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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: 1, 1, 1 result, different first party: 1, 1, 1 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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: 1, 1, 1 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different first party: 1, 1, 1 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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
  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: 1, 1, 1 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different first party: 1, 1, 1 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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: 1, 1, 1 result, different first party: 1, 1, 1 unsupported: false, false, false passed: false, false, false test failed: false, false, false
getDirectorynavigator.storage.getDirectory exposes a location for storing files to web content. In some cases, these files may be shared across tabs.
  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: 5465a603-de27-44f5-b8c4-707bfb613e2e, 78421fc4-bf96-4cca-890a-80da7897dc6d, 80b14108-7165-4df7-a9e6-ff02143416a6 result, different first party: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 716abdfe-395d-427a-95f5-86b590a83dbe, 74b40c1c-a56c-422c-8ec2-977bc24c84e1, a1abfa62-2197-4ef7-a6aa-1649c66a9829 result, different first party: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 result, different first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 unsupported: false, false, false passed: false, false, false test failed: false, false, false
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 result, different first party: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: true, true, true passed: undefined test failed: false, false, false
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 result, different first party: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: true, true, true passed: undefined test failed: false, false, false
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 result, different first party: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: true, true, true passed: undefined test failed: false, false, false
  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: c28bfb99-bfe7-484e-91ee-401936368f8e, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6, 41f02047-71ab-44db-a34c-341407f5d677 result, different first party: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: false, false, false passed: true, true, true test failed: false, false, false
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
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 result, different first party: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: true, true, true passed: undefined test failed: false, false, false
  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: 48c217f0-1bef-4ff9-a86a-e02c452b3090, 52225fb2-48b7-4a6d-8cba-f85356406aba, 5616596f-2317-42fc-bd3f-f8e6bc122d3e result, different first party: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: a5be31f4-aa0a-4843-923b-3c4f83f5a928, e31de4a2-0c0c-4125-b3cc-46d11e5579f9, 8db17cd7-36fc-475c-8d65-e14f8da75dc6 result, different first party: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: false, false, false passed: true, true, true test failed: false, false, false
H1 connectionHTTP/1.x are the classic web connection protocols. If these connections are re-used across websites, they can be used to track users.
  write: async (secret) => { await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${secret}`, {cache: "no-store"}); } read: async () => { let response = await fetch(`https://h1.privacytests2.org:8901/?mode=read`, {cache: "no-store"}); return await response.text(); } result, same first party: 5465a603-de27-44f5-b8c4-707bfb613e2e, 78421fc4-bf96-4cca-890a-80da7897dc6d, 80b14108-7165-4df7-a9e6-ff02143416a6 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${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: 716abdfe-395d-427a-95f5-86b590a83dbe, 74b40c1c-a56c-422c-8ec2-977bc24c84e1, a1abfa62-2197-4ef7-a6aa-1649c66a9829 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${secret}`, {cache: "no-store"}); } read: async () => { let response = await fetch(`https://h1.privacytests2.org:8901/?mode=read`, {cache: "no-store"}); return await response.text(); } result, same first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${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: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826, cf35c52d-e97f-4820-82eb-d8054844f2c1 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${secret}`, {cache: "no-store"}); } read: async () => { let response = await fetch(`https://h1.privacytests2.org:8901/?mode=read`, {cache: "no-store"}); return await response.text(); } result, same first party: e37747b4-8740-49ba-9270-601151aaf726, e2e870e7-134c-4209-b335-78130b0eb740, af1f42ee-1067-499d-8093-d4d19b5c49a6 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${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: b71a2d50-2167-4614-a844-3de0e93814fb, 87735b1f-b9af-4abe-8b23-8eb0096d3907, e9f1e434-9ee8-4cdb-b17e-75370f35bfa9 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${secret}`, {cache: "no-store"}); } read: async () => { let response = await fetch(`https://h1.privacytests2.org:8901/?mode=read`, {cache: "no-store"}); return await response.text(); } result, same first party: c28bfb99-bfe7-484e-91ee-401936368f8e, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6, 41f02047-71ab-44db-a34c-341407f5d677 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${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: c24314e8-1afc-4d9a-96a4-bc75e5d99b58, aa3c8308-259e-464e-aa4f-6e3b827d137c, 358e00ee-1af1-443e-8d23-1fa8923e03fc, 7fe8a160-092e-4a52-81cd-841a2600cf16, cafc6b09-49db-407e-950e-bab9a6e60e9f result, different first party: , , , , unsupported: false, false, false, false, false passed: true, true, true, true, true test failed: false, false, false, false, false
  write: async (secret) => { await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${secret}`, {cache: "no-store"}); } read: async () => { let response = await fetch(`https://h1.privacytests2.org:8901/?mode=read`, {cache: "no-store"}); return await response.text(); } result, same first party: 91977509-fee5-471e-9ccb-9dd38fc58a67, aab3ddfd-726f-4857-83c6-8d44ea5e6bb4, 43c85c36-872d-485b-852e-5b322a7c7d45 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${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: 48c217f0-1bef-4ff9-a86a-e02c452b3090, 52225fb2-48b7-4a6d-8cba-f85356406aba, 5616596f-2317-42fc-bd3f-f8e6bc122d3e result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { await fetch(`https://h1.privacytests2.org:8901/?mode=write&secret=${secret}`, {cache: "no-store"}); } read: async () => { let response = await fetch(`https://h1.privacytests2.org:8901/?mode=read`, {cache: "no-store"}); return await response.text(); } result, same first party: a5be31f4-aa0a-4843-923b-3c4f83f5a928, e31de4a2-0c0c-4125-b3cc-46d11e5579f9, 8db17cd7-36fc-475c-8d65-e14f8da75dc6 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
H2 connectionHTTP/2 is a web connection protocol introduced in 2015. Some browsers re-use HTTP/2 connections across websites and can thus be used to track users.
  write: async (secret) => { await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${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: 5465a603-de27-44f5-b8c4-707bfb613e2e, 78421fc4-bf96-4cca-890a-80da7897dc6d, 80b14108-7165-4df7-a9e6-ff02143416a6 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${secret}`, {cache: "no-store"}); } read: async () => { let response = await fetch(`https://h2.privacytests2.org:8902/?mode=read`, {cache: "no-store"}); return await response.text(); } result, same first party: 716abdfe-395d-427a-95f5-86b590a83dbe, 74b40c1c-a56c-422c-8ec2-977bc24c84e1, a1abfa62-2197-4ef7-a6aa-1649c66a9829 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${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: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${secret}`, {cache: "no-store"}); } read: async () => { let response = await fetch(`https://h2.privacytests2.org:8902/?mode=read`, {cache: "no-store"}); return await response.text(); } result, same first party: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826, cf35c52d-e97f-4820-82eb-d8054844f2c1 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${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: e37747b4-8740-49ba-9270-601151aaf726, e2e870e7-134c-4209-b335-78130b0eb740, af1f42ee-1067-499d-8093-d4d19b5c49a6 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${secret}`, {cache: "no-store"}); } read: async () => { let response = await fetch(`https://h2.privacytests2.org:8902/?mode=read`, {cache: "no-store"}); return await response.text(); } result, same first party: b71a2d50-2167-4614-a844-3de0e93814fb, 87735b1f-b9af-4abe-8b23-8eb0096d3907, e9f1e434-9ee8-4cdb-b17e-75370f35bfa9 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${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: c28bfb99-bfe7-484e-91ee-401936368f8e, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6, 41f02047-71ab-44db-a34c-341407f5d677 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${secret}`, {cache: "no-store"}); } read: async () => { let response = await fetch(`https://h2.privacytests2.org:8902/?mode=read`, {cache: "no-store"}); return await response.text(); } result, same first party: c24314e8-1afc-4d9a-96a4-bc75e5d99b58, aa3c8308-259e-464e-aa4f-6e3b827d137c, 358e00ee-1af1-443e-8d23-1fa8923e03fc, 7fe8a160-092e-4a52-81cd-841a2600cf16, cafc6b09-49db-407e-950e-bab9a6e60e9f result, different first party: , , , , unsupported: false, false, false, false, false passed: true, true, true, true, true test failed: false, false, false, false, false
  write: async (secret) => { await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${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: 91977509-fee5-471e-9ccb-9dd38fc58a67, aab3ddfd-726f-4857-83c6-8d44ea5e6bb4, 43c85c36-872d-485b-852e-5b322a7c7d45 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${secret}`, {cache: "no-store"}); } read: async () => { let response = await fetch(`https://h2.privacytests2.org:8902/?mode=read`, {cache: "no-store"}); return await response.text(); } result, same first party: 48c217f0-1bef-4ff9-a86a-e02c452b3090, 52225fb2-48b7-4a6d-8cba-f85356406aba, 5616596f-2317-42fc-bd3f-f8e6bc122d3e result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { await fetch(`https://h2.privacytests2.org:8902/?mode=write&secret=${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: a5be31f4-aa0a-4843-923b-3c4f83f5a928, e31de4a2-0c0c-4125-b3cc-46d11e5579f9, 8db17cd7-36fc-475c-8d65-e14f8da75dc6 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
H3 connectionHTTP/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.
  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: 5fcf99659587ca49c54586f6d505cbb9, 5d76a70d801e4a982ab0c4e65530a94c, cdd242c020a71e4a10dfbba7f4a1fa1b result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: e1cb2ff2840ef2a50aac3b685bb4dc7e, 3c2b01a0c14dcd9d076aefbe09fb4a41, d3fa01fe7d48d340a4656dc07a7cb6fd result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: fdcf9ac09f78791078e042247f5b5d3e, cfa69f450b2f23d0def4c01dce9ff72b, 16c8c140d49f49afedefa93aa89d5f0f result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 5ba37e131d452e3f6cd5ba3d8f522362, 1e20c9747e6cdc096dbf6ba851d344b3, 1086151e0df1e4917cc9328b5e87f4c6 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1b45ad1a6fccfedfeb15f20234eee9b0, 20e2ca57b91dfe10994211078a8a4505, 301ae4b8c4f6206c6556d1d135507441 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 45ea34e643f84f84023b721c0eae49b4, 8936f32dd7b85a0407dca1bafe14abab, d38ef4efbcd95b6b2187663773576677 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 7bf692570ce48a51964bc8f6cbf45742, 52021abd95efcb36cf4ad16b43bc95e6, 9e0db5e923f87e426ee8116bdf9ea4fa result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
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
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 passed: undefined test failed: false, false, false
  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: e1c0e5e4f7e433b81fae192baafd8cc3, 09659cf72a830f04c17594ff1ffa1ee7, de76102c0d0a9da9d9196c8fcab250ea result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 5d3222f269b71e0b8ba39b93dee2986f, 2716933832909d73f7cb654b95107bd3, f5c8421617afed5217981b9827d9aab8 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
HSTS cacheThe 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."
  write: set HSTS flag read: read HSTS flag result, same first party: not tested, not tested, not tested result, different first party: Used http, Used http, Used http unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: set HSTS flag read: read HSTS flag result, same first party: not tested, not tested, not tested result, different first party: Upgraded to https, Upgraded to https, Upgraded to https unsupported: false, false, false passed: false, false, false test failed: false, false, false
  write: set HSTS flag read: read HSTS flag result, same first party: not tested, not tested, not tested result, different first party: Upgraded to https, Upgraded to https, Upgraded to https unsupported: false, false, false passed: false, false, false test failed: false, false, false
  write: set HSTS flag read: read HSTS flag result, same first party: not tested, not tested, not tested result, different first party: Used http, Used http, Used http unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: null read: null result, same first party: , , result, different first party: HTTPS used by default; no HSTS cache issue expected, HTTPS used by default; no HSTS cache issue expected, HTTPS used by default; no HSTS cache issue expected unsupported: , , passed: true, true, true test failed: false, false, false
  write: null read: null result, same first party: , , result, different first party: HTTPS used by default; no HSTS cache issue expected, HTTPS used by default; no HSTS cache issue expected, HTTPS used by default; no HSTS cache issue expected unsupported: , , passed: true, true, true test failed: false, false, false
  write: set HSTS flag read: read HSTS flag result, same first party: not tested, not tested, not tested result, different first party: Upgraded to https, Upgraded to https, Upgraded to https unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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
  write: null read: null result, same first party: , , result, different first party: HTTPS used by default; no HSTS cache issue expected, HTTPS used by default; no HSTS cache issue expected, HTTPS used by default; no HSTS cache issue expected unsupported: , , passed: true, true, true test failed: false, false, false
  write: set HSTS flag read: read HSTS flag result, same first party: not tested, not tested, not tested result, different first party: Upgraded to https, Upgraded to https, Upgraded to https unsupported: false, false, false passed: false, false, false test failed: false, false, false
  write: set HSTS flag read: read HSTS flag result, same first party: not tested, not tested, not tested result, different first party: Upgraded to https, Upgraded to https, Upgraded to https unsupported: false, false, false passed: false, false, false test failed: false, false, false
iframe cacheAn 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.
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
image cacheCaching of images in web browsers is a standard behavior. But if that cache leaks between websites, it can be abused for cross-site tracking.
  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: 1, 1, 1 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different first party: 1, 1, 1 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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: 1, 1, 1 result, different first party: 1, 1, 1 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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: 1, 1, 1 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different first party: 1, 1, 1 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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
  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: 1, 1, 1 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different first party: 1, 1, 1 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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: 1, 1, 1 result, different first party: 1, 1, 1 unsupported: false, false, false passed: false, false, false test failed: false, false, false
indexedDBThe IndexedDB API exposes a transactional database to web pages. That database can be used to track users across websites, unless it is partitioned.
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same first party: 5465a603-de27-44f5-b8c4-707bfb613e2e, 78421fc4-bf96-4cca-890a-80da7897dc6d, 80b14108-7165-4df7-a9e6-ff02143416a6 result, different first party: Error: The user denied permission to access the database., Error: The user denied permission to access the database., Error: The user denied permission to access the database. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same first party: 716abdfe-395d-427a-95f5-86b590a83dbe, 74b40c1c-a56c-422c-8ec2-977bc24c84e1, a1abfa62-2197-4ef7-a6aa-1649c66a9829 result, different first party: Error: The user denied permission to access the database., Error: The user denied permission to access the database., Error: The user denied permission to access the database. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 result, different first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same first party: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826, cf35c52d-e97f-4820-82eb-d8054844f2c1 result, different first party: undefined unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same first party: e37747b4-8740-49ba-9270-601151aaf726, e2e870e7-134c-4209-b335-78130b0eb740, af1f42ee-1067-499d-8093-d4d19b5c49a6 result, different first party: undefined unsupported: false, false, false passed: true, true, true test failed: false, false, false
write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same first party: Error: A mutation operation was attempted on a database that did not allow mutations., Error: A mutation operation was attempted on a database that did not allow mutations., Error: A mutation operation was attempted on a database that did not allow mutations. result, different first party: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: true, true, true passed: undefined test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same first party: c28bfb99-bfe7-484e-91ee-401936368f8e, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6, 41f02047-71ab-44db-a34c-341407f5d677 result, different first party: Error: The user denied permission to access the database., Error: The user denied permission to access the database., Error: The user denied permission to access the database. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same first party: c24314e8-1afc-4d9a-96a4-bc75e5d99b58, aa3c8308-259e-464e-aa4f-6e3b827d137c, 358e00ee-1af1-443e-8d23-1fa8923e03fc, 7fe8a160-092e-4a52-81cd-841a2600cf16, cafc6b09-49db-407e-950e-bab9a6e60e9f result, different first party: undefined unsupported: false, false, false, false, false passed: true, true, true, true, true test failed: false, false, false, false, false
write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same first party: Error: A mutation operation was attempted on a database that did not allow mutations., Error: A mutation operation was attempted on a database that did not allow mutations., Error: A mutation operation was attempted on a database that did not allow mutations. result, different first party: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: true, true, true passed: undefined test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same first party: 48c217f0-1bef-4ff9-a86a-e02c452b3090, 52225fb2-48b7-4a6d-8cba-f85356406aba, 5616596f-2317-42fc-bd3f-f8e6bc122d3e result, different first party: Error: The user denied permission to access the database., Error: The user denied permission to access the database., Error: The user denied permission to access the database. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same first party: a5be31f4-aa0a-4843-923b-3c4f83f5a928, e31de4a2-0c0c-4125-b3cc-46d11e5579f9, 8db17cd7-36fc-475c-8d65-e14f8da75dc6 result, different first party: Error: The user denied permission to access the database., Error: The user denied permission to access the database., Error: The user denied permission to access the database. unsupported: false, false, false passed: true, true, true test failed: false, false, false
localStorageThe 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.
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same first party: 5465a603-de27-44f5-b8c4-707bfb613e2e, 78421fc4-bf96-4cca-890a-80da7897dc6d, 80b14108-7165-4df7-a9e6-ff02143416a6 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same first party: 716abdfe-395d-427a-95f5-86b590a83dbe, 74b40c1c-a56c-422c-8ec2-977bc24c84e1, a1abfa62-2197-4ef7-a6aa-1649c66a9829 result, different first party: Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 result, different first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same first party: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826, cf35c52d-e97f-4820-82eb-d8054844f2c1 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same first party: e37747b4-8740-49ba-9270-601151aaf726, e2e870e7-134c-4209-b335-78130b0eb740, af1f42ee-1067-499d-8093-d4d19b5c49a6 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same first party: b71a2d50-2167-4614-a844-3de0e93814fb, 87735b1f-b9af-4abe-8b23-8eb0096d3907, e9f1e434-9ee8-4cdb-b17e-75370f35bfa9 result, different first party: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same first party: c28bfb99-bfe7-484e-91ee-401936368f8e, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6, 41f02047-71ab-44db-a34c-341407f5d677 result, different first party: Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same first party: c24314e8-1afc-4d9a-96a4-bc75e5d99b58, aa3c8308-259e-464e-aa4f-6e3b827d137c, 358e00ee-1af1-443e-8d23-1fa8923e03fc, 7fe8a160-092e-4a52-81cd-841a2600cf16, cafc6b09-49db-407e-950e-bab9a6e60e9f result, different first party: , , , , unsupported: false, false, false, false, false passed: true, true, true, true, true test failed: false, false, false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same first party: 91977509-fee5-471e-9ccb-9dd38fc58a67, aab3ddfd-726f-4857-83c6-8d44ea5e6bb4, 43c85c36-872d-485b-852e-5b322a7c7d45 result, different first party: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same first party: 48c217f0-1bef-4ff9-a86a-e02c452b3090, 52225fb2-48b7-4a6d-8cba-f85356406aba, 5616596f-2317-42fc-bd3f-f8e6bc122d3e result, different first party: Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same first party: a5be31f4-aa0a-4843-923b-3c4f83f5a928, e31de4a2-0c0c-4125-b3cc-46d11e5579f9, 8db17cd7-36fc-475c-8d65-e14f8da75dc6 result, different first party: Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document. unsupported: false, false, false passed: true, true, true test failed: false, false, false
locksnavigator.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.
  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: 5465a603-de27-44f5-b8c4-707bfb613e2e, 78421fc4-bf96-4cca-890a-80da7897dc6d, 80b14108-7165-4df7-a9e6-ff02143416a6 result, different first party: Error: The request was denied., Error: The request was denied., Error: The request was denied. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 716abdfe-395d-427a-95f5-86b590a83dbe, 74b40c1c-a56c-422c-8ec2-977bc24c84e1, a1abfa62-2197-4ef7-a6aa-1649c66a9829 result, different first party: Error: The request was denied., Error: The request was denied., Error: The request was denied. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 result, different first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826, cf35c52d-e97f-4820-82eb-d8054844f2c1 result, different first party: Error: LockManager.query: query() is not allowed in this context, Error: LockManager.query: query() is not allowed in this context, Error: LockManager.query: query() is not allowed in this context unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: e37747b4-8740-49ba-9270-601151aaf726, e2e870e7-134c-4209-b335-78130b0eb740, af1f42ee-1067-499d-8093-d4d19b5c49a6 result, different first party: Error: LockManager.query: query() is not allowed in this context, Error: LockManager.query: query() is not allowed in this context, Error: LockManager.query: query() is not allowed in this context unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: b71a2d50-2167-4614-a844-3de0e93814fb, 87735b1f-b9af-4abe-8b23-8eb0096d3907, e9f1e434-9ee8-4cdb-b17e-75370f35bfa9 result, different first party: Error: LockManager.query: query() is not allowed in this context, Error: LockManager.query: query() is not allowed in this context, Error: LockManager.query: query() is not allowed in this context unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: c28bfb99-bfe7-484e-91ee-401936368f8e, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6, 41f02047-71ab-44db-a34c-341407f5d677 result, different first party: Error: The request was denied., Error: The request was denied., Error: The request was denied. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: c24314e8-1afc-4d9a-96a4-bc75e5d99b58, aa3c8308-259e-464e-aa4f-6e3b827d137c, 358e00ee-1af1-443e-8d23-1fa8923e03fc, 7fe8a160-092e-4a52-81cd-841a2600cf16, cafc6b09-49db-407e-950e-bab9a6e60e9f 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: true, true, true, true, true test failed: false, false, false, false, false
  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: 91977509-fee5-471e-9ccb-9dd38fc58a67, aab3ddfd-726f-4857-83c6-8d44ea5e6bb4, 43c85c36-872d-485b-852e-5b322a7c7d45 result, different first party: Error: LockManager.query: query() is not allowed in this context, Error: LockManager.query: query() is not allowed in this context, Error: LockManager.query: query() is not allowed in this context unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 48c217f0-1bef-4ff9-a86a-e02c452b3090, 52225fb2-48b7-4a6d-8cba-f85356406aba, 5616596f-2317-42fc-bd3f-f8e6bc122d3e result, different first party: Error: The request was denied., Error: The request was denied., Error: The request was denied. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: a5be31f4-aa0a-4843-923b-3c4f83f5a928, e31de4a2-0c0c-4125-b3cc-46d11e5579f9, 8db17cd7-36fc-475c-8d65-e14f8da75dc6 result, different first party: Error: The request was denied., Error: The request was denied., Error: The request was denied. unsupported: false, false, false passed: true, true, true test failed: false, false, false
prefetch cacheA 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.
  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: 1, 1, 1 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different first party: 1, 1, 1 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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: 1, 1, 1 result, different first party: 1, 1, 1 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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: 1, 1, 1 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
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 result, different first party: Error: No requests received, Error: No requests received, Error: No requests received unsupported: true, true, true passed: undefined test failed: false, false, false
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 result, different first party: Error: No requests received, Error: No requests received, Error: No requests received unsupported: true, true, true passed: undefined test failed: false, false, false
  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: 1, 1, 1 result, different first party: 1, 1, 1 unsupported: false, false, false passed: false, false, false test failed: false, false, false
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
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 result, different first party: Error: No requests received, Error: No requests received, Error: No requests received unsupported: true, true, true passed: undefined test failed: false, false, false
  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: 1, 1, 1 result, different first party: 1, 1, 1 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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: 1, 1, 1 result, different first party: 1, 1, 1 unsupported: false, false, false passed: false, false, false test failed: false, false, false
ServiceWorkerThe 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.
  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: <html> <head><title>404 Not Found</title></head> <body> <center><h1>404 Not Found</h1></center> <hr><center>nginx/1.18.0 (Ubuntu)</center> </body> </html> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> , <html> <head><title>404 Not Found</title></head> <body> <center><h1>404 Not Found</h1></center> <hr><center>nginx/1.18.0 (Ubuntu)</center> </body> </html> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> , <html> <head><title>404 Not Found</title></head> <body> <center><h1>404 Not Found</h1></center> <hr><center>nginx/1.18.0 (Ubuntu)</center> </body> </html> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> result, different first party: Error: Failed to register a ServiceWorker for scope ('https://test-pages.privacytests2.org/') with script ('https://test-pages.privacytests2.org/serviceWorker.js'): The user denied permission to use Service Worker., Error: Failed to register a ServiceWorker for scope ('https://test-pages.privacytests2.org/') with script ('https://test-pages.privacytests2.org/serviceWorker.js'): The user denied permission to use Service Worker., Error: Failed to register a ServiceWorker for scope ('https://test-pages.privacytests2.org/') with script ('https://test-pages.privacytests2.org/serviceWorker.js'): The user denied permission to use Service Worker. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: <html> <head><title>404 Not Found</title></head> <body> <center><h1>404 Not Found</h1></center> <hr><center>nginx/1.18.0 (Ubuntu)</center> </body> </html> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> , <html> <head><title>404 Not Found</title></head> <body> <center><h1>404 Not Found</h1></center> <hr><center>nginx/1.18.0 (Ubuntu)</center> </body> </html> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> , <html> <head><title>404 Not Found</title></head> <body> <center><h1>404 Not Found</h1></center> <hr><center>nginx/1.18.0 (Ubuntu)</center> </body> </html> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> result, different first party: Error: Failed to register a ServiceWorker for scope ('https://test-pages.privacytests2.org/') with script ('https://test-pages.privacytests2.org/serviceWorker.js'): The user denied permission to use Service Worker., Error: Failed to register a ServiceWorker for scope ('https://test-pages.privacytests2.org/') with script ('https://test-pages.privacytests2.org/serviceWorker.js'): The user denied permission to use Service Worker., Error: Failed to register a ServiceWorker for scope ('https://test-pages.privacytests2.org/') with script ('https://test-pages.privacytests2.org/serviceWorker.js'): The user denied permission to use Service Worker. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: <html> <head><title>404 Not Found</title></head> <body> <center><h1>404 Not Found</h1></center> <hr><center>nginx/1.18.0 (Ubuntu)</center> </body> </html> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> , <html> <head><title>404 Not Found</title></head> <body> <center><h1>404 Not Found</h1></center> <hr><center>nginx/1.18.0 (Ubuntu)</center> </body> </html> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> , <html> <head><title>404 Not Found</title></head> <body> <center><h1>404 Not Found</h1></center> <hr><center>nginx/1.18.0 (Ubuntu)</center> </body> </html> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> result, different first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 unsupported: false, false, false passed: true, true, true test failed: false, false, false
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: Error: navigator.serviceWorker is undefined, Error: navigator.serviceWorker is undefined, Error: navigator.serviceWorker is undefined result, different first party: Error: navigator.serviceWorker is undefined, Error: navigator.serviceWorker is undefined, Error: navigator.serviceWorker is undefined unsupported: true, true, true passed: undefined test failed: false, false, false
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=${key}`); } read: async () => { console.log("trying to register the serviceworker now..."); const registration = await Promise.race([ navigator.serviceWorker.register('serviceWorker.js'), sleepMs(500) ]); if (registration === undefined) { // We timed out or otherwise failed. throw new Error("ServiceWorker registration failed"); } console.log(registration); await navigator.serviceWorker.ready; console.log("service worker ready"); await sleepMs(100); let response = await fetch("serviceworker-read"); return await response.text(); } result, same first party: Error: navigator.serviceWorker is undefined, Error: navigator.serviceWorker is undefined, Error: navigator.serviceWorker is undefined result, different first party: Error: navigator.serviceWorker is undefined, Error: navigator.serviceWorker is undefined, Error: navigator.serviceWorker is undefined unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { if (!navigator.serviceWorker) { throw new Error("Unsupported"); } let registration = await navigator.serviceWorker.register( 'serviceWorker.js'); console.log(registration); await navigator.serviceWorker.ready; console.log("service worker ready"); await sleepMs(100); await fetch(`serviceworker-write?secret=${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: Error: navigator.serviceWorker is undefined, Error: navigator.serviceWorker is undefined, Error: navigator.serviceWorker is undefined result, different first party: Error: navigator.serviceWorker is undefined, Error: navigator.serviceWorker is undefined, Error: navigator.serviceWorker is undefined unsupported: true, true, true passed: undefined test failed: false, false, false
  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: <html> <head><title>404 Not Found</title></head> <body> <center><h1>404 Not Found</h1></center> <hr><center>nginx/1.18.0 (Ubuntu)</center> </body> </html> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> , <html> <head><title>404 Not Found</title></head> <body> <center><h1>404 Not Found</h1></center> <hr><center>nginx/1.18.0 (Ubuntu)</center> </body> </html> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> , <html> <head><title>404 Not Found</title></head> <body> <center><h1>404 Not Found</h1></center> <hr><center>nginx/1.18.0 (Ubuntu)</center> </body> </html> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> result, different first party: Error: Failed to register a ServiceWorker for scope ('https://test-pages.privacytests2.org/') with script ('https://test-pages.privacytests2.org/serviceWorker.js'): The user denied permission to use Service Worker., Error: Failed to register a ServiceWorker for scope ('https://test-pages.privacytests2.org/') with script ('https://test-pages.privacytests2.org/serviceWorker.js'): The user denied permission to use Service Worker., Error: Failed to register a ServiceWorker for scope ('https://test-pages.privacytests2.org/') with script ('https://test-pages.privacytests2.org/serviceWorker.js'): The user denied permission to use Service Worker. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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
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=${key}`); } read: async () => { console.log("trying to register the serviceworker now..."); const registration = await Promise.race([ navigator.serviceWorker.register('serviceWorker.js'), sleepMs(500) ]); if (registration === undefined) { // We timed out or otherwise failed. throw new Error("ServiceWorker registration failed"); } console.log(registration); await navigator.serviceWorker.ready; console.log("service worker ready"); await sleepMs(100); let response = await fetch("serviceworker-read"); return await response.text(); } result, same first party: Error: navigator.serviceWorker is undefined, Error: navigator.serviceWorker is undefined, Error: navigator.serviceWorker is undefined result, different first party: Error: navigator.serviceWorker is undefined, Error: navigator.serviceWorker is undefined, Error: navigator.serviceWorker is undefined unsupported: true, true, true passed: undefined test failed: false, false, false
  write: async (key) => { if (!navigator.serviceWorker) { throw new Error("Unsupported"); } let registration = await navigator.serviceWorker.register( 'serviceWorker.js'); console.log(registration); await navigator.serviceWorker.ready; console.log("service worker ready"); await sleepMs(100); await fetch(`serviceworker-write?secret=${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: <html> <head><title>404 Not Found</title></head> <body> <center><h1>404 Not Found</h1></center> <hr><center>nginx/1.18.0 (Ubuntu)</center> </body> </html> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> , <html> <head><title>404 Not Found</title></head> <body> <center><h1>404 Not Found</h1></center> <hr><center>nginx/1.18.0 (Ubuntu)</center> </body> </html> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> , <html> <head><title>404 Not Found</title></head> <body> <center><h1>404 Not Found</h1></center> <hr><center>nginx/1.18.0 (Ubuntu)</center> </body> </html> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> result, different first party: Error: Failed to register a ServiceWorker for scope ('https://test-pages.privacytests2.org/') with script ('https://test-pages.privacytests2.org/serviceWorker.js'): The user denied permission to use Service Worker., Error: Failed to register a ServiceWorker for scope ('https://test-pages.privacytests2.org/') with script ('https://test-pages.privacytests2.org/serviceWorker.js'): The user denied permission to use Service Worker., Error: Failed to register a ServiceWorker for scope ('https://test-pages.privacytests2.org/') with script ('https://test-pages.privacytests2.org/serviceWorker.js'): The user denied permission to use Service Worker. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: <html> <head><title>404 Not Found</title></head> <body> <center><h1>404 Not Found</h1></center> <hr><center>nginx/1.18.0 (Ubuntu)</center> </body> </html> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> , <html> <head><title>404 Not Found</title></head> <body> <center><h1>404 Not Found</h1></center> <hr><center>nginx/1.18.0 (Ubuntu)</center> </body> </html> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> , <html> <head><title>404 Not Found</title></head> <body> <center><h1>404 Not Found</h1></center> <hr><center>nginx/1.18.0 (Ubuntu)</center> </body> </html> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> <!-- a padding to disable MSIE and Chrome friendly error page --> result, different first party: Error: Failed to register a ServiceWorker for scope ('https://test-pages.privacytests2.org/') with script ('https://test-pages.privacytests2.org/serviceWorker.js'): The user denied permission to use Service Worker., Error: Failed to register a ServiceWorker for scope ('https://test-pages.privacytests2.org/') with script ('https://test-pages.privacytests2.org/serviceWorker.js'): The user denied permission to use Service Worker., Error: Failed to register a ServiceWorker for scope ('https://test-pages.privacytests2.org/') with script ('https://test-pages.privacytests2.org/serviceWorker.js'): The user denied permission to use Service Worker. unsupported: false, false, false passed: true, true, true test failed: false, false, false
SharedWorkerThe 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.
  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: 5465a603-de27-44f5-b8c4-707bfb613e2e, 78421fc4-bf96-4cca-890a-80da7897dc6d, 80b14108-7165-4df7-a9e6-ff02143416a6 result, different first party: Error: no SharedWorker message received, Error: no SharedWorker message received, Error: no SharedWorker message received unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 716abdfe-395d-427a-95f5-86b590a83dbe, 74b40c1c-a56c-422c-8ec2-977bc24c84e1, a1abfa62-2197-4ef7-a6aa-1649c66a9829 result, different first party: Error: no SharedWorker message received, Error: no SharedWorker message received, Error: no SharedWorker message received unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 result, different first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826, cf35c52d-e97f-4820-82eb-d8054844f2c1 result, different first party: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: e37747b4-8740-49ba-9270-601151aaf726, e2e870e7-134c-4209-b335-78130b0eb740, af1f42ee-1067-499d-8093-d4d19b5c49a6 result, different first party: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: b71a2d50-2167-4614-a844-3de0e93814fb, 87735b1f-b9af-4abe-8b23-8eb0096d3907, e9f1e434-9ee8-4cdb-b17e-75370f35bfa9 result, different first party: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: c28bfb99-bfe7-484e-91ee-401936368f8e, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6, 41f02047-71ab-44db-a34c-341407f5d677 result, different first party: Error: no SharedWorker message received, Error: no SharedWorker message received, Error: no SharedWorker message received unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: c24314e8-1afc-4d9a-96a4-bc75e5d99b58, aa3c8308-259e-464e-aa4f-6e3b827d137c, 358e00ee-1af1-443e-8d23-1fa8923e03fc, 7fe8a160-092e-4a52-81cd-841a2600cf16, cafc6b09-49db-407e-950e-bab9a6e60e9f result, different first party: Error: Unsupported, Error: Unsupported, Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: false, false, false, false, false passed: true, true, true, true, true test failed: false, false, false, false, false
  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: 91977509-fee5-471e-9ccb-9dd38fc58a67, aab3ddfd-726f-4857-83c6-8d44ea5e6bb4, 43c85c36-872d-485b-852e-5b322a7c7d45 result, different first party: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 48c217f0-1bef-4ff9-a86a-e02c452b3090, 52225fb2-48b7-4a6d-8cba-f85356406aba, 5616596f-2317-42fc-bd3f-f8e6bc122d3e result, different first party: Error: no SharedWorker message received, Error: no SharedWorker message received, Error: no SharedWorker message received unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: a5be31f4-aa0a-4843-923b-3c4f83f5a928, e31de4a2-0c0c-4125-b3cc-46d11e5579f9, 8db17cd7-36fc-475c-8d65-e14f8da75dc6 result, different first party: Error: no SharedWorker message received, Error: no SharedWorker message received, Error: no SharedWorker message received unsupported: false, false, false passed: true, true, true test failed: false, false, false
TLS Session IDThe 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.
  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: 1fbb83f276e04f175840092f146cab14b86a7f30962321ea87c4ff30b0bf3109, e1cb23338b0c501feb9ced972e8c24331426f6eecddc50ebf32d25ab1d6a61bb, f4fee78ef746ae0bf74f70a0d34912f063c4520ab0e47ad66f88b9c1616bf804 result, different first party: 66999ba43dce8bd2b2082597f3d6c4040af79b509129a15c1433bfe05902ecd4, ce9bcd86a1a002b05406592cfd86ebd6f5620d3e78e29cc80d626cbfebd3fa23, cd4d0499ab5e6d8a22e233b37c43cd803903ae857071e5876eb32391c0c9dbec unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: d7ed578a6954d4ffa1c4f61cedcd8e3d64a1ab90150d4eada35c314142ced0bb, 26cf64ece9e410c810622d199b6f96e8b52e1ea47f7427c1d705f9d846fce227, 7db4a646460d86186406d7a935852ec8410d3297c609530eac5850da378d39ac result, different first party: d912833cf1596f4e3689c128452a816243b02024221a472e4786ce9820357a5f, fe5b691b2ec8520a94f4e790d284a00d179bb02caca6945aa20ab31a6de613cd, e051daa7b1bb1bdb60e8e3495a493b4bc6388bfd8d8fec3e9bee1d67ca2ca147 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 4a7638ef22941af7f6c7b502eb6b6f54cb9af0b4d597d0319d69991733e375ce, 9f802f965142062277758dda45fb586829f960fa305d8a27fa4187fc259188ea, 19d9d7b3350ba7d12ac84688f8c655bcde9e5374d62039f9df6ca0f37c8d4240 result, different first party: f2a315f5bb41fcd02f17b9e889c5d138a15dcfba99147ab66a5646bf9c2fa809, 8da8012e1e14c2e0b450b2b373b1fe740c55c9106efeabe5750eb114c76a8b92, abb9b995d069a6548354c940c12580a5ac0185536ed00683bc8b3373027869c9 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 39d8f201f641a052fa76df8896cc664b03f94578d3820e03b4414a93326303e3, 5cf63044100b5d83a1526c0a7b8139ba943e50f24129a7be96eb09468db4a99c, 5fb02d2dc26dbe6c84cc7ffc85f945c341b7e96c0e193eed3e94d7b49015f3d2 result, different first party: df66f2ebc97106ccc772e5dcb91d60e41bf3faff840b0677d5971b895e97b7d1, bd4e614e4765adb435bdb14b55e32a36f9ea1bdf10160772c376c6aa00ce56ee, 14366758844580876089cc0f28d1d61f4a94347edc63fae10dbf975fba1d5a6f unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1236cb8447fd2f979efa8ec08655b2a869a6f5eff20de6067ba99fc881a88215, 5aaa7842bd5b58962a689583b60f2e3e5b88411a28eb387cc54ff4bc958e2c66, af32c68866d74be2e01f542f91c42374c816c31cab032e92d2bcae681dd27c99 result, different first party: 959a703df4e904da9fd405871f7b2e75a325c4a3299ea9f8b1cf7f1158a6ecc0, a7864b54969b4127b7eddec3288ed8b8b73f7b31126863148ed26b70a49c4c42, 6cde9eff9a7e4dd13c83cc07f473d3f80466125ada8b201c3adc763461c52b48 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 5c478ec1074625ab5cb705e0416b7a86fe7b777f409585ed19af561b8b2aa850, ba3f112005c9f2a92cbf412a810c067b052e56fe30c9f688bd4ae6ba2b4cc63b, 57773f482dd4c7f307fd52cde7b9c536a48de15781b4bdf8f13687d6f82ddf93 result, different first party: 4c0fc4ef5533fce0a0a1c98ceb97c147ad336aeba2f635f41b6442d0285ac927, 4a6cc27a63946b99e296f93bb5821b244063a8213e6abc321670639c18b24d5a, 93daddb1606c0b412968570c7e4b71e3b08845027468280cc6c902b87962aca8 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 0bf34c8b112cff8dd10b5b6944d9f4cf0351a228ec4ce246932004dd2220020b, f816f77d09eb4570d00d2125c49f672a6a8b90eac13b2f3408d0ae6a2d46a7f5, 5a223f23f2c00ec6c4ff04baee7ad0ba227543053f9655a61ab0a6887d702359 result, different first party: 1e9415c7d25f2f9dae636ebfc24a3905f1e1c340e4186564eea167710b34709c, 5ae6ff4b7ca647f4f934567d349cb64f3dc10194136b269a3c9f00b2ec221e5e, 4198458ff8ba85989f2329826c34d8ff0456c1d3f5635aae16398fd4c9c81766 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: f2ae99aa2bfae2a48da0d66bca381718e3c5f33e36de1b967504ed11699baf70, d1cdc4d36ab70b808548ba37ab7d23d9909bf7e473080be0c36949a7bbfa53a9, 1443fb38a159cf0358e9891031a166e5e241f9185c5471cc472756667cb70d4f, 12b6b80a0b010549685a35eae2d88568b31a4adf2cbb1a3d4637651df6e9c885, d3295b6ee0bf9861c2360708875fdd9ffd46a706eb52d3828edd57b7f07ca694 result, different first party: e00de10d42eae942c370b6fb5c0391a8cd086e16c7b26a86e13ad4431eb88808, ec582d061138f512f4e118961b0f13b1341eceb1e57df73060b9a22e093c649e, 97b06ea8f13746114144e257f39a302de8e248284163b0e7cd47d8bd6d82cfd3, d7dd87e8db66803fdc6e5a2bd959cab134cab015cd3040cc15a0f13ecb6803f9, 47bd28bb8b0988bf33323a80779b708b473335a2531b9fb002f6111a2b6bed4a unsupported: false, false, false, false, false passed: true, true, true, true, true test failed: false, false, false, false, false
  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: e5fa0994b9fcb6df8bb3c6c65607d03e68d960e86d0b5645f8cae0321d45436f, 16913fe98a34ee3f2f7f0392c8d600907e00ee0c673fa47ce2f23ebc0e7dae90, e4ad6808018ba9edc5cab0d56646acb9a6900b15bd7ab239fc1724bae6d7fa1d result, different first party: 64d355afcb782a846d7f76d0c697b4c96a46e1090373dc0139c7bc66014de72c, d0f232e88035e06984f79e188ee68aa3c2a6014d2c55991e26db758671bc3856, 2038879b19599b778bc22c88da43a11bbc0bcc661a69614973147c17db792763 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: ef514527ec2d4d2e9a6ff314875cd6a0b4814bb8c3964d7ce944f01107b5bd7a, 544df1a365eedd06a3226086478abb9c2f438c3ac1c81b5bc8bba6cbfbaf69f1, 37ffade11fcab23de9f1cbec759084f3323abad461a6f08370daa7fda87b7f17 result, different first party: 1508cbd5b0c9ef9cbccd4107205fee3bb70c457995ec6b901cf27f87c650d15e, fb814c63c6a59fb8a11f33d61c8040f847055817b280de566cfaed8b01d06ea9, 382a69fe7343c3db10c6e2be3857cdd18253053177b7724264eeabda2c001737 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 8d9a3ddaf887928ef12ec1b0d3d7f693f84e7f631c6769d65d053e008b37c00a, 063eda7fb9ec05bee742bd035c2f50ace7fb718eac28951438053acd39781aad, 420aba7a509eb6a851bfbcc68126d9b390f3be152c80dc8c722e49f90324806f result, different first party: a21bc70ba54ce74cf3c35febf4739d95350b3034a5b6e961b8f5ad6c84a53a17, e8b61153889b5fa7c507767c7977e74e00d553224fa6817ea141dbbbed5c30ce, 022c0bbb517753a0a31242d2375795116fd76a243882f5426c2573412b0fdcf5 unsupported: false, false, false passed: true, true, true test failed: false, false, false
Web SQL DatabaseThe Web SQL Database is a deprecated web API for storing data in an SQL database.
  write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same first party: 5465a603-de27-44f5-b8c4-707bfb613e2e, 78421fc4-bf96-4cca-890a-80da7897dc6d, 80b14108-7165-4df7-a9e6-ff02143416a6 result, different first party: Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same first party: 716abdfe-395d-427a-95f5-86b590a83dbe, 74b40c1c-a56c-422c-8ec2-977bc24c84e1, a1abfa62-2197-4ef7-a6aa-1649c66a9829 result, different first party: Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 result, different first party: Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same first party: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function result, different first party: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function unsupported: false, false, false passed: undefined test failed: true, true, true
  write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same first party: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function result, different first party: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function unsupported: false, false, false passed: undefined test failed: true, true, true
  write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same first party: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function result, different first party: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function unsupported: false, false, false passed: undefined test failed: true, true, true
  write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same first party: c28bfb99-bfe7-484e-91ee-401936368f8e, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6, 41f02047-71ab-44db-a34c-341407f5d677 result, different first party: Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same first party: Error: Web SQL is deprecated, Error: Web SQL is deprecated, Error: Web SQL is deprecated, Error: Web SQL is deprecated, Error: Web SQL is deprecated result, different first party: Error: Web SQL is deprecated, Error: Web SQL is deprecated, Error: Web SQL is deprecated, Error: Web SQL is deprecated, Error: Web SQL is deprecated unsupported: false, false, false, false, false passed: undefined test failed: true, true, true, true, true
  write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same first party: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function result, different first party: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function unsupported: false, false, false passed: undefined test failed: true, true, true
  write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same first party: 48c217f0-1bef-4ff9-a86a-e02c452b3090, 52225fb2-48b7-4a6d-8cba-f85356406aba, 5616596f-2317-42fc-bd3f-f8e6bc122d3e result, different first party: Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same first party: a5be31f4-aa0a-4843-923b-3c4f83f5a928, e31de4a2-0c0c-4125-b3cc-46d11e5579f9, 8db17cd7-36fc-475c-8d65-e14f8da75dc6 result, different first party: Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts. unsupported: false, false, false passed: true, true, true test failed: false, false, false
XMLHttpRequest cacheSimilar to the newer Fetch API, any resource received may be cached by the browser. The cache is potentially vulnerable to cross-site tracking attack.
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different first party: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
Navigation tests Which 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.referrerThe 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.
  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/ result, different first party: https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/ unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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/ result, different first party: https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/ unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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/ result, different first party: https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/ unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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/ result, different first party: https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/ unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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/ result, different first party: https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/ unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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/ result, different first party: https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/ unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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/ result, different first party: https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/ unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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
  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/ result, different first party: https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/ unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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/ result, different first party: https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/ unsupported: false, false, false passed: false, false, false test failed: false, false, false
  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/ result, different first party: https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/, https://test-pages.privacytests2.org/ unsupported: false, false, false passed: false, false, false test failed: false, false, false
sessionStorageThe 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.
  write: (secret) => sessionStorage.setItem("secret", secret) read: () => sessionStorage.getItem("secret") result, same first party: 5465a603-de27-44f5-b8c4-707bfb613e2e, 78421fc4-bf96-4cca-890a-80da7897dc6d, 80b14108-7165-4df7-a9e6-ff02143416a6 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => sessionStorage.setItem("secret", secret) read: () => sessionStorage.getItem("secret") result, same first party: 716abdfe-395d-427a-95f5-86b590a83dbe, 74b40c1c-a56c-422c-8ec2-977bc24c84e1, a1abfa62-2197-4ef7-a6aa-1649c66a9829 result, different first party: Error: Failed to read the 'sessionStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'sessionStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'sessionStorage' property from 'Window': Access is denied for this document. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => sessionStorage.setItem("secret", secret) read: () => sessionStorage.getItem("secret") result, same first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 result, different first party: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, 0e22765a-3b45-4d4f-96e1-155b36d72016 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  write: (secret) => sessionStorage.setItem("secret", secret) read: () => sessionStorage.getItem("secret") result, same first party: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826, cf35c52d-e97f-4820-82eb-d8054844f2c1 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => sessionStorage.setItem("secret", secret) read: () => sessionStorage.getItem("secret") result, same first party: e37747b4-8740-49ba-9270-601151aaf726, e2e870e7-134c-4209-b335-78130b0eb740, af1f42ee-1067-499d-8093-d4d19b5c49a6 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => sessionStorage.setItem("secret", secret) read: () => sessionStorage.getItem("secret") result, same first party: b71a2d50-2167-4614-a844-3de0e93814fb, 87735b1f-b9af-4abe-8b23-8eb0096d3907, e9f1e434-9ee8-4cdb-b17e-75370f35bfa9 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => sessionStorage.setItem("secret", secret) read: () => sessionStorage.getItem("secret") result, same first party: c28bfb99-bfe7-484e-91ee-401936368f8e, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6, 41f02047-71ab-44db-a34c-341407f5d677 result, different first party: Error: Failed to read the 'sessionStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'sessionStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'sessionStorage' property from 'Window': Access is denied for this document. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => sessionStorage.setItem("secret", secret) read: () => sessionStorage.getItem("secret") result, same first party: c24314e8-1afc-4d9a-96a4-bc75e5d99b58, aa3c8308-259e-464e-aa4f-6e3b827d137c, 358e00ee-1af1-443e-8d23-1fa8923e03fc, 7fe8a160-092e-4a52-81cd-841a2600cf16, cafc6b09-49db-407e-950e-bab9a6e60e9f result, different first party: , , , , unsupported: false, false, false, false, false passed: true, true, true, true, true test failed: false, false, false, false, false
  write: (secret) => sessionStorage.setItem("secret", secret) read: () => sessionStorage.getItem("secret") result, same first party: 91977509-fee5-471e-9ccb-9dd38fc58a67, aab3ddfd-726f-4857-83c6-8d44ea5e6bb4, 43c85c36-872d-485b-852e-5b322a7c7d45 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => sessionStorage.setItem("secret", secret) read: () => sessionStorage.getItem("secret") result, same first party: 48c217f0-1bef-4ff9-a86a-e02c452b3090, 52225fb2-48b7-4a6d-8cba-f85356406aba, 5616596f-2317-42fc-bd3f-f8e6bc122d3e result, different first party: Error: Failed to read the 'sessionStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'sessionStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'sessionStorage' property from 'Window': Access is denied for this document. unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => sessionStorage.setItem("secret", secret) read: () => sessionStorage.getItem("secret") result, same first party: a5be31f4-aa0a-4843-923b-3c4f83f5a928, e31de4a2-0c0c-4125-b3cc-46d11e5579f9, 8db17cd7-36fc-475c-8d65-e14f8da75dc6 result, different first party: Error: Failed to read the 'sessionStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'sessionStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'sessionStorage' property from 'Window': Access is denied for this document. unsupported: false, false, false passed: true, true, true test failed: false, false, false
window.nameThe 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.
  write: (secret) => window.name = "name_" + secret read: () => window.name result, same first party: name_5465a603-de27-44f5-b8c4-707bfb613e2e, name_78421fc4-bf96-4cca-890a-80da7897dc6d, name_80b14108-7165-4df7-a9e6-ff02143416a6 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => window.name = "name_" + secret read: () => window.name result, same first party: name_716abdfe-395d-427a-95f5-86b590a83dbe, name_74b40c1c-a56c-422c-8ec2-977bc24c84e1, name_a1abfa62-2197-4ef7-a6aa-1649c66a9829 result, different first party: name_716abdfe-395d-427a-95f5-86b590a83dbe, name_74b40c1c-a56c-422c-8ec2-977bc24c84e1, name_a1abfa62-2197-4ef7-a6aa-1649c66a9829 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  write: (secret) => window.name = "name_" + secret read: () => window.name result, same first party: name_499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, name_649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, name_0e22765a-3b45-4d4f-96e1-155b36d72016 result, different first party: name_499d70a2-e9f7-41f7-998e-f5bc1ea9d72a, name_649e5b9f-17af-47a2-9bb7-d04dfd4c3b51, name_0e22765a-3b45-4d4f-96e1-155b36d72016 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  write: (secret) => window.name = "name_" + secret read: () => window.name result, same first party: name_28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4, name_3b1a07e6-6d4a-4740-8bfa-f2901dcd7826, name_cf35c52d-e97f-4820-82eb-d8054844f2c1 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => window.name = "name_" + secret read: () => window.name result, same first party: name_e37747b4-8740-49ba-9270-601151aaf726, name_e2e870e7-134c-4209-b335-78130b0eb740, name_af1f42ee-1067-499d-8093-d4d19b5c49a6 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => window.name = "name_" + secret read: () => window.name result, same first party: name_b71a2d50-2167-4614-a844-3de0e93814fb, name_87735b1f-b9af-4abe-8b23-8eb0096d3907, name_e9f1e434-9ee8-4cdb-b17e-75370f35bfa9 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => window.name = "name_" + secret read: () => window.name result, same first party: name_c28bfb99-bfe7-484e-91ee-401936368f8e, name_91c652e2-c96b-4855-ba1a-b3b4410bd9f6, name_41f02047-71ab-44db-a34c-341407f5d677 result, different first party: name_c28bfb99-bfe7-484e-91ee-401936368f8e, name_91c652e2-c96b-4855-ba1a-b3b4410bd9f6, name_41f02047-71ab-44db-a34c-341407f5d677 unsupported: false, false, false passed: false, false, false test failed: false, false, false
  write: (secret) => window.name = "name_" + secret read: () => window.name result, same first party: name_c24314e8-1afc-4d9a-96a4-bc75e5d99b58, name_aa3c8308-259e-464e-aa4f-6e3b827d137c, name_358e00ee-1af1-443e-8d23-1fa8923e03fc, name_7fe8a160-092e-4a52-81cd-841a2600cf16, name_cafc6b09-49db-407e-950e-bab9a6e60e9f result, different first party: , , , , unsupported: false, false, false, false, false passed: true, true, true, true, true test failed: false, false, false, false, false
  write: (secret) => window.name = "name_" + secret read: () => window.name result, same first party: name_91977509-fee5-471e-9ccb-9dd38fc58a67, name_aab3ddfd-726f-4857-83c6-8d44ea5e6bb4, name_43c85c36-872d-485b-852e-5b322a7c7d45 result, different first party: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => window.name = "name_" + secret read: () => window.name result, same first party: name_48c217f0-1bef-4ff9-a86a-e02c452b3090, name_52225fb2-48b7-4a6d-8cba-f85356406aba, name_5616596f-2317-42fc-bd3f-f8e6bc122d3e result, different first party: name_48c217f0-1bef-4ff9-a86a-e02c452b3090, name_52225fb2-48b7-4a6d-8cba-f85356406aba, name_5616596f-2317-42fc-bd3f-f8e6bc122d3e unsupported: false, false, false passed: false, false, false test failed: false, false, false
  write: (secret) => window.name = "name_" + secret read: () => window.name result, same first party: name_a5be31f4-aa0a-4843-923b-3c4f83f5a928, name_e31de4a2-0c0c-4125-b3cc-46d11e5579f9, name_8db17cd7-36fc-475c-8d65-e14f8da75dc6 result, different first party: name_a5be31f4-aa0a-4843-923b-3c4f83f5a928, name_e31de4a2-0c0c-4125-b3cc-46d11e5579f9, name_8db17cd7-36fc-475c-8d65-e14f8da75dc6 unsupported: false, false, false passed: false, false, false test failed: false, false, false
HTTPS tests Which browsers use encrypted network connections whenever possible?
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 websiteChecks 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.
  passed: false,false,false result: Insecure website loaded,Insecure website loaded,Insecure website loaded
  passed: false,false,false result: Insecure website loaded,Insecure website loaded,Insecure website loaded
  passed: false,false,false result: Insecure website loaded,Insecure website loaded,Insecure website loaded
  passed: false,false,false result: Insecure website loaded,Insecure website loaded,Insecure website loaded
  passed: true,true,true result: Insecure website never loaded,Insecure website never loaded,Insecure website never loaded
  passed: true,true,true result: Insecure website never loaded,Insecure website never loaded,Insecure website never loaded
  passed: false,false,false result: Insecure website loaded,Insecure website loaded,Insecure website loaded
  passed: false,false,false,false,false result: Insecure website loaded,Insecure website loaded,Insecure website loaded,Insecure website loaded,Insecure website loaded
  passed: true,true,true result: Insecure website never loaded,Insecure website never loaded,Insecure website never loaded
  passed: false,false,false result: Insecure website loaded,Insecure website loaded,Insecure website loaded
  passed: false,false,false result: Insecure website loaded,Insecure website loaded,Insecure website loaded
Upgradable addressChecks to see if an insecure address entered into the browser's address bar is upgraded to HTTPS whenever possible.
  upgraded: true,true,true passed: true,true,true
  upgraded: true,false,false passed: true,false,false
  upgraded: false,false,false passed: false,false,false
  upgraded: true,true,true passed: true,true,true
  upgraded: true,true,true passed: true,true,true
  upgraded: true,true,true passed: true,true,true
  upgraded: false,false,false passed: false,false,false
  upgraded: false,false,false,false,false passed: false,false,false,false,false
  upgraded: true,true,true passed: true,true,true
  upgraded: false,false,false passed: false,false,false
  upgraded: false,false,false passed: false,false,false
Upgradable hyperlinkChecks to see if the user has clicked on a hyperlink to an insecure address, if the browser upgrades that address to HTTPS whenever possible.
  upgraded: true,true,true passed: true,true,true
  upgraded: true,false,false passed: true,false,false
  upgraded: false,false,false passed: false,false,false
  upgraded: true,true,true passed: true,true,true
  upgraded: true,true,true passed: true,true,true
  upgraded: true,true,true passed: true,true,true
  upgraded: false,false,false passed: false,false,false
  upgraded: false,false,false,false,false passed: false,false,false,false,false
  upgraded: true,true,true passed: true,true,true
  upgraded: false,false,false passed: false,false,false
  upgraded: false,false,false passed: false,false,false
Upgradable imageChecks to see if the browser attempts to upgrade an insecure address for an image to HTTPS whenever possible.
  passed: true,true,true result: upgraded,upgraded,upgraded
  passed: true,true,true result: upgraded,upgraded,upgraded
  passed: true,true,true result: upgraded,upgraded,upgraded
  passed: false,false,false result: loaded insecurely,loaded insecurely,loaded insecurely
  passed: true,true,true result: upgraded,upgraded,upgraded
  passed: true,true,true result: upgraded,upgraded,upgraded
  passed: true,true,true result: upgraded,upgraded,upgraded
  passed: false,false,false,false,false result: loaded insecurely,loaded insecurely,loaded insecurely,loaded insecurely,loaded insecurely
  passed: true,true,true result: upgraded,upgraded,upgraded
  passed: true,true,true result: upgraded,upgraded,upgraded
  passed: true,true,true result: upgraded,upgraded,upgraded
Upgradable scriptChecks to see if the browser attempts to upgrade an insecure address for an script to HTTPS whenever possible.
  passed: true,true,true result: blocked,blocked,blocked
  passed: true,true,true result: blocked,blocked,blocked
  passed: true,true,true result: blocked,blocked,blocked
  passed: true,true,true result: blocked,blocked,blocked
  passed: true,true,true result: upgraded,upgraded,upgraded
  passed: true,true,true result: upgraded,upgraded,upgraded
  passed: true,true,true result: blocked,blocked,blocked
  passed: true,true,true,true,true result: blocked,blocked,blocked,blocked,blocked
  passed: true,true,true result: upgraded,upgraded,upgraded
  passed: true,true,true result: blocked,blocked,blocked
  passed: true,true,true result: blocked,blocked,blocked
Misc tests Which browsers provide additional assorted privacy protections?
This category includes tests for the presence of miscellaneous privacy features
ECH enabledEncrypted Client Hello (ECH) is a new protocol that hides the website you are visiting from third-party network eavesdroppers.
  SNI_status: plaintext passed: false,false,false
  SNI_status: plaintext passed: false,false,false
  SNI_status: plaintext passed: false,false,false
  SNI_status: plaintext passed: false,false,false
  SNI_status: plaintext passed: false,false,false
  SNI_status: plaintext passed: false,false,false
  SNI_status: plaintext passed: false,false,false
  SNI_status: plaintext passed: false,false,false,false,false
  SNI_status: plaintext passed: false,false,false
  SNI_status: plaintext passed: false,false,false
  SNI_status: plaintext passed: false,false,false
GPC enabled first-partyThe 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.
  header value: 1 passed: true,true,true
  header value: undefined passed: false,false,false
  header value: undefined passed: false,false,false
  header value: undefined passed: false,false,false
  header value: undefined passed: false,false,false
  header value: undefined passed: false,false,false
  header value: undefined passed: false,false,false
  header value: undefined passed: false,false,false,false,false
  header value: undefined passed: false,false,false
  header value: undefined passed: false,false,false
  header value: undefined passed: false,false,false
GPC enabled third-partyThe 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.
  sec-gpc: 1 passed: true,true,true
  passed: false,false,false
  passed: false,false,false
  passed: false,false,false
  passed: false,false,false
  passed: false,false,false
  passed: false,false,false
  passed: false,false,false,false,false
  passed: false,false,false
  passed: false,false,false
  passed: false,false,false
IP address leakIP addresses can be used to uniquely identify a large percentage of users. A proxy, VPN, or Tor can mask a user's IP address.
  passed: false,false,false
  passed: false,false,false
  passed: false,false,false
  passed: false,false,false
  passed: false,false,false
  passed: false,false,false
  passed: false,false,false
  passed: false,false,false,false,false
  passed: true,true,true
  passed: false,false,false
  passed: false,false,false
Stream isolationBrowsers that use Tor can use a different Tor circuit per top-level website.
write: () => { if (!usingTor) { throw new Error("Unsupported"); } } read: async () => { if (usingTor) { return ipAddress; } else { throw new Error("Unsupported"); } } unsupported: true,true,true readSameFirstParty: Error: Unsupported,Error: Unsupported,Error: Unsupported readDifferentFirstParty: Error: Unsupported,Error: Unsupported,Error: Unsupported testFailed: false,false,false
write: () => { if (!usingTor) { throw new Error("Unsupported"); } } read: async () => { if (usingTor) { return ipAddress; } else { throw new Error("Unsupported"); } } unsupported: true,true,true readSameFirstParty: Error: Unsupported,Error: Unsupported,Error: Unsupported readDifferentFirstParty: Error: Unsupported,Error: Unsupported,Error: Unsupported testFailed: false,false,false
write: () => { if (!usingTor) { throw new Error("Unsupported"); } } read: async () => { if (usingTor) { return ipAddress; } else { throw new Error("Unsupported"); } } unsupported: true,true,true readSameFirstParty: Error: Unsupported,Error: Unsupported,Error: Unsupported readDifferentFirstParty: Error: Unsupported,Error: Unsupported,Error: Unsupported testFailed: false,false,false
write: () => { if (!usingTor) { throw new Error("Unsupported"); } } read: async () => { if (usingTor) { return ipAddress; } else { throw new Error("Unsupported"); } } unsupported: true,true,true readSameFirstParty: Error: Unsupported,Error: Unsupported,Error: Unsupported readDifferentFirstParty: Error: Unsupported,Error: Unsupported,Error: Unsupported testFailed: false,false,false
write: () => { if (!usingTor) { throw new Error("Unsupported"); } } read: async () => { if (usingTor) { return ipAddress; } else { throw new Error("Unsupported"); } } unsupported: true,true,true readSameFirstParty: Error: Unsupported,Error: Unsupported,Error: Unsupported readDifferentFirstParty: Error: Unsupported,Error: Unsupported,Error: Unsupported testFailed: false,false,false
write: () => { if (!usingTor) { throw new Error("Unsupported"); } } read: async () => { if (usingTor) { return ipAddress; } else { throw new Error("Unsupported"); } } unsupported: true,true,true readSameFirstParty: Error: Unsupported,Error: Unsupported,Error: Unsupported readDifferentFirstParty: Error: Unsupported,Error: Unsupported,Error: Unsupported testFailed: false,false,false
write: () => { if (!usingTor) { throw new Error("Unsupported"); } } read: async () => { if (usingTor) { return ipAddress; } else { throw new Error("Unsupported"); } } unsupported: true,true,true readSameFirstParty: Error: Unsupported,Error: Unsupported,Error: Unsupported readDifferentFirstParty: Error: Unsupported,Error: Unsupported,Error: Unsupported testFailed: false,false,false
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
  write: () => { if (!usingTor) { throw new Error("Unsupported"); } } read: async () => { if (usingTor) { return ipAddress; } else { throw new Error("Unsupported"); } } unsupported: true,false,false readSameFirstParty: Error: Unsupported,185.220.101.138,2a0b:f4c0:16c:8::1 readDifferentFirstParty: 2a0b:f4c0:16c:4::1,2a0b:f4c0:16c:15::1,2a0b:f4c2:2::36 testFailed: false,false,false passed: ,true,true
write: () => { if (!usingTor) { throw new Error("Unsupported"); } } read: async () => { if (usingTor) { return ipAddress; } else { throw new Error("Unsupported"); } } unsupported: true,true,true readSameFirstParty: Error: Unsupported,Error: Unsupported,Error: Unsupported readDifferentFirstParty: Error: Unsupported,Error: Unsupported,Error: Unsupported testFailed: false,false,false
write: () => { if (!usingTor) { throw new Error("Unsupported"); } } read: async () => { if (usingTor) { return ipAddress; } else { throw new Error("Unsupported"); } } unsupported: true,true,true readSameFirstParty: Error: Unsupported,Error: Unsupported,Error: Unsupported readDifferentFirstParty: Error: Unsupported,Error: Unsupported,Error: Unsupported testFailed: false,false,false
Tor enabledThe 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.
  IsTorExit: false,false,false passed: false,false,false
  IsTorExit: false,false,false passed: false,false,false
  IsTorExit: false,false,false passed: false,false,false
  IsTorExit: false,false,false passed: false,false,false
  IsTorExit: false,false,false passed: false,false,false
  IsTorExit: false,false,false passed: false,false,false
  IsTorExit: false,false,false passed: false,false,false
  IsTorExit: false,false,false,false,false passed: false,false,false,false,false
  IsTorExit: false,true,true passed: false,true,true
  IsTorExit: false,false,false passed: false,false,false
  IsTorExit: false,false,false passed: false,false,false
Fingerprinting resistance tests Which 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 heightHeight of the user's screen in pixels.
  expression: undefined desired expression: undefined actual value: 1302,1298,1302 desired value: undefined passed: true,true,true
  expression: undefined desired expression: undefined actual value: 1440,1440,1440 desired value: undefined passed: false,false,false
  expression: undefined desired expression: undefined actual value: 1440,1440,1440 desired value: undefined passed: false,false,false
  expression: undefined desired expression: undefined actual value: 1440,1440,1440 desired value: undefined passed: false,false,false
  expression: undefined desired expression: undefined actual value: 900,900,900 desired value: undefined passed: true,true,true
  expression: undefined desired expression: undefined actual value: 1000,1000,1000 desired value: undefined passed: true,true,true
  expression: undefined desired expression: undefined actual value: 1440,1440,1440 desired value: undefined passed: false,false,false
  expression: undefined desired expression: undefined actual value: 1440,1440,1440,1440,1440 desired value: undefined passed: false,false,false,false,false
  expression: undefined desired expression: undefined actual value: 1000,1000,1000 desired value: undefined passed: true,true,true
  expression: undefined desired expression: undefined actual value: 1440,1440,1440 desired value: undefined passed: false,false,false
  expression: undefined desired expression: undefined actual value: 1440,1440,1440 desired value: undefined passed: false,false,false
Media query screen widthWidth of the user's screen in pixels.
  expression: undefined desired expression: undefined actual value: 1201,1205,1203 desired value: undefined passed: true,true,true
  expression: undefined desired expression: undefined actual value: 2560,2560,2560 desired value: undefined passed: false,false,false
  expression: undefined desired expression: undefined actual value: 2560,2560,2560 desired value: undefined passed: false,false,false
  expression: undefined desired expression: undefined actual value: 2560,2560,2560 desired value: undefined passed: false,false,false
  expression: undefined desired expression: undefined actual value: 1600,1600,1600 desired value: undefined passed: true,true,true
  expression: undefined desired expression: undefined actual value: 1000,1000,1000 desired value: undefined passed: true,true,true
  expression: undefined desired expression: undefined actual value: 2560,2560,2560 desired value: undefined passed: false,false,false
  expression: undefined desired expression: undefined actual value: 2560,2560,2560,2560,2560 desired value: undefined passed: false,false,false,false,false
  expression: undefined desired expression: undefined actual value: 1000,1000,1000 desired value: undefined passed: true,true,true
  expression: undefined desired expression: undefined actual value: 2560,2560,2560 desired value: undefined passed: false,false,false
  expression: undefined desired expression: undefined actual value: 2560,2560,2560 desired value: undefined passed: false,false,false
outerHeightHeight of the browser window in pixels, including browser chrome.
  expression: outerHeight desired expression: undefined actual value: 1302,1298,1302 desired value: undefined passed: true,true,true
  expression: outerHeight desired expression: undefined actual value: 1371,1371,1371 desired value: undefined passed: false,false,false
  expression: outerHeight desired expression: undefined actual value: 1371,1371,1371 desired value: undefined passed: false,false,false
  expression: outerHeight desired expression: undefined actual value: 1040,1040,1040 desired value: undefined passed: false,false,false
  expression: outerHeight desired expression: undefined actual value: 900,900,900 desired value: undefined passed: true,true,true
  expression: outerHeight desired expression: undefined actual value: 1000,1000,1000 desired value: undefined passed: true,true,true
  expression: outerHeight desired expression: undefined actual value: 1061,1061,1061 desired value: undefined passed: false,false,false
  expression: outerHeight desired expression: undefined actual value: 1415,1415,1415,1415,1415 desired value: undefined passed: false,false,false,false,false
  expression: outerHeight desired expression: undefined actual value: 1000,1000,1000 desired value: undefined passed: true,true,true
  expression: outerHeight desired expression: undefined actual value: 1371,1371,1371 desired value: undefined passed: false,false,false
  expression: outerHeight desired expression: undefined actual value: 1371,1371,1371 desired value: undefined passed: false,false,false
screen.heightHeight of the user's screen, in pixels.
  expression: screen.height desired expression: undefined actual value: 1302,1298,1302 desired value: undefined passed: true,true,true
  expression: screen.height desired expression: undefined actual value: 1440,1440,1440 desired value: undefined passed: false,false,false
  expression: screen.height desired expression: undefined actual value: 1440,1440,1440 desired value: undefined passed: false,false,false
  expression: screen.height desired expression: undefined actual value: 1440,1440,1440 desired value: undefined passed: false,false,false
  expression: screen.height desired expression: undefined actual value: 900,900,900 desired value: undefined passed: true,true,true
  expression: screen.height desired expression: undefined actual value: 1000,1000,1000 desired value: undefined passed: true,true,true
  expression: screen.height desired expression: undefined actual value: 1440,1440,1440 desired value: undefined passed: false,false,false
  expression: screen.height desired expression: undefined actual value: 1440,1440,1440,1440,1440 desired value: undefined passed: false,false,false,false,false
  expression: screen.height desired expression: undefined actual value: 1000,1000,1000 desired value: undefined passed: true,true,true
  expression: screen.height desired expression: undefined actual value: 1440,1440,1440 desired value: undefined passed: false,false,false
  expression: screen.height desired expression: undefined actual value: 1440,1440,1440 desired value: undefined passed: false,false,false
screen.widthWidth of the user's screen, in pixels.
  expression: screen.width desired expression: undefined actual value: 1201,1205,1203 desired value: undefined passed: true,true,true
  expression: screen.width desired expression: undefined actual value: 2560,2560,2560 desired value: undefined passed: false,false,false
  expression: screen.width desired expression: undefined actual value: 2560,2560,2560 desired value: undefined passed: false,false,false
  expression: screen.width desired expression: undefined actual value: 2560,2560,2560 desired value: undefined passed: false,false,false
  expression: screen.width desired expression: undefined actual value: 1600,1600,1600 desired value: undefined passed: true,true,true
  expression: screen.width desired expression: undefined actual value: 1000,1000,1000 desired value: undefined passed: true,true,true
  expression: screen.width desired expression: undefined actual value: 2560,2560,2560 desired value: undefined passed: false,false,false
  expression: screen.width desired expression: undefined actual value: 2560,2560,2560,2560,2560 desired value: undefined passed: false,false,false,false,false
  expression: screen.width desired expression: undefined actual value: 1000,1000,1000 desired value: undefined passed: true,true,true
  expression: screen.width desired expression: undefined actual value: 2560,2560,2560 desired value: undefined passed: false,false,false
  expression: screen.width desired expression: undefined actual value: 2560,2560,2560 desired value: undefined passed: false,false,false
screenXPosition, in pixels, of the left edge of the browser window on screen.
  expression: screenX desired expression: undefined actual value: 5,7,0 desired value: undefined passed: true,true,true
  expression: screenX desired expression: undefined actual value: 22,22,22 desired value: undefined passed: false,false,false
  expression: screenX desired expression: undefined actual value: 22,22,22 desired value: undefined passed: false,false,false
  expression: screenX desired expression: undefined actual value: 4,4,4 desired value: undefined passed: true,true,true
  expression: screenX desired expression: undefined actual value: 0,0,0 desired value: undefined passed: true,true,true
  expression: screenX desired expression: undefined actual value: 0,0,0 desired value: undefined passed: true,true,true
  expression: screenX desired expression: undefined actual value: 320,320,320 desired value: undefined passed: false,false,false
  expression: screenX desired expression: undefined actual value: -1835,-1835,-1835,-1835,-1835 desired value: undefined passed: false,false,false,false,false
  expression: screenX desired expression: undefined actual value: 0,0,0 desired value: undefined passed: true,true,true
  expression: screenX desired expression: undefined actual value: 22,22,22 desired value: undefined passed: false,false,false
  expression: screenX desired expression: undefined actual value: 22,22,22 desired value: undefined passed: false,false,false
screenYPosition, in pixels, of the top edge of the browser window on screen.
  expression: screenY desired expression: undefined actual value: 1,0,8 desired value: undefined passed: true,true,true
  expression: screenY desired expression: undefined actual value: 47,47,47 desired value: undefined passed: false,false,false
  expression: screenY desired expression: undefined actual value: 47,47,47 desired value: undefined passed: false,false,false
  expression: screenY desired expression: undefined actual value: 25,25,25 desired value: undefined passed: false,false,false
  expression: screenY desired expression: undefined actual value: 0,0,0 desired value: undefined passed: true,true,true
  expression: screenY desired expression: undefined actual value: 0,0,0 desired value: undefined passed: true,true,true
  expression: screenY desired expression: undefined actual value: 202,202,202 desired value: undefined passed: false,false,false
  expression: screenY desired expression: undefined actual value: 25,25,25,25,25 desired value: undefined passed: false,false,false,false,false
  expression: screenY desired expression: undefined actual value: 0,0,0 desired value: undefined passed: true,true,true
  expression: screenY desired expression: undefined actual value: 47,47,47 desired value: undefined passed: false,false,false
  expression: screenY desired expression: undefined actual value: 47,47,47 desired value: undefined passed: false,false,false
System font detectionWeb pages can detect the presence of a font installed on the user's system. The presence or absence of various fonts is commonly used to fingerprint users.
  expression: undefined desired expression: undefined actual value: undefined desired value: undefined passed: true,true,true
  expression: undefined desired expression: undefined actual value: undefined desired value: undefined passed: false,false,false
  expression: undefined desired expression: undefined actual value: undefined desired value: undefined passed: false,false,false
  expression: undefined desired expression: undefined actual value: undefined desired value: undefined passed: false,false,false
  expression: undefined desired expression: undefined actual value: undefined desired value: undefined passed: true,true,true
  expression: undefined desired expression: undefined actual value: undefined desired value: undefined passed: true,true,true
  expression: undefined desired expression: undefined actual value: undefined desired value: undefined passed: false,false,false
  expression: undefined desired expression: undefined actual value: undefined desired value: undefined passed: true,true,true,true,true
  expression: undefined desired expression: undefined actual value: undefined desired value: undefined passed: true,true,true
  expression: undefined desired expression: undefined actual value: undefined desired value: undefined passed: false,false,false
  expression: undefined desired expression: undefined actual value: undefined desired value: undefined passed: false,false,false
Tracking query parameter tests Which 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.)`
__hsfpHubSpot tracking parameter
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
__hsscHubSpot tracking parameter
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
__hstcHubSpot tracking parameter
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
__sDrip.com email address tracking parameter
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
_hsencHubSpot tracking parameter
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
_openstatYandex tracking parameter
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
dclidDoubleClick Click ID (Google)
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
fbclidFacebook Click Identifier
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
gclidGoogle Click Identifier
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
hsCtaTrackingHubSpot tracking parameter
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
mc_eidMailchimp Email ID (email recipient's address)
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
mkt_tokAdobe Marketo tracking parameter
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
ml_subscriberMailerLite email tracking
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
ml_subscriber_hashMailerLite email tracking
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
msclkidMicrosoft Click ID
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
oly_anon_idOmeda marketing 'anonymous' customer id
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
oly_enc_idOmeda marketing 'known' customer id
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
rb_clickidUnknown high-entropy tracking parameter
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
s_cidAdobe Site Catalyst tracking parameter
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
vero_convVero tracking parameter
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
vero_idVero tracking parameter
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
wickedidWicked Reports e-commerce tracking
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
yclidYandex Click ID
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  passed: true,true,true
  passed: true,true,true
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
  value: 6460730637534513 passed: false,false,false
Tracker content blocking tests Which 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.`
AdobeTests whether the browser blocks the page from loading the tracker at https://munchkin.marketo.net/munchkin.js
  url: https://munchkin.marketo.net/munchkin.js passed: true,true,true
  url: https://munchkin.marketo.net/munchkin.js passed: false,false,false
  url: https://munchkin.marketo.net/munchkin.js passed: false,false,false
  url: https://munchkin.marketo.net/munchkin.js passed: true,true,true
  url: https://munchkin.marketo.net/munchkin.js passed: true,true,true
  url: https://munchkin.marketo.net/munchkin.js passed: true,true,true
  url: https://munchkin.marketo.net/munchkin.js passed: false,false,false
  url: https://munchkin.marketo.net/munchkin.js passed: false,false,false,false,false
  url: https://munchkin.marketo.net/munchkin.js passed: false,false,false
  url: https://munchkin.marketo.net/munchkin.js passed: false,false,false
  url: https://munchkin.marketo.net/munchkin.js passed: false,false,false
Adobe Audience ManagerTests whether the browser blocks the page from loading the tracker at https://dpm.demdex.net/ibs
  url: https://dpm.demdex.net/ibs passed: true,true,true
  url: https://dpm.demdex.net/ibs passed: false,false,false
  url: https://dpm.demdex.net/ibs passed: false,false,false
  url: https://dpm.demdex.net/ibs passed: true,true,true
  url: https://dpm.demdex.net/ibs passed: true,true,true
  url: https://dpm.demdex.net/ibs passed: true,true,true
  url: https://dpm.demdex.net/ibs passed: false,false,false
  url: https://dpm.demdex.net/ibs passed: false,false,false,false,false
  url: https://dpm.demdex.net/ibs passed: false,false,false
  url: https://dpm.demdex.net/ibs passed: false,false,false
  url: https://dpm.demdex.net/ibs passed: false,false,false
Amazon adsystemTests whether the browser blocks the page from loading the tracker at https://s.amazon-adsystem.com/dcm
  url: https://s.amazon-adsystem.com/dcm passed: true,true,true
  url: https://s.amazon-adsystem.com/dcm passed: false,false,false
  url: https://s.amazon-adsystem.com/dcm passed: false,false,false
  url: https://s.amazon-adsystem.com/dcm passed: true,true,true
  url: https://s.amazon-adsystem.com/dcm passed: true,true,true
  url: https://s.amazon-adsystem.com/dcm passed: true,true,true
  url: https://s.amazon-adsystem.com/dcm passed: false,false,false
  url: https://s.amazon-adsystem.com/dcm passed: false,false,false,false,false
  url: https://s.amazon-adsystem.com/dcm passed: false,false,false
  url: https://s.amazon-adsystem.com/dcm passed: false,false,false
  url: https://s.amazon-adsystem.com/dcm passed: false,false,false
AppNexusTests whether the browser blocks the page from loading the tracker at https://ib.adnxs.com/px?id=178248&t=1
  url: https://ib.adnxs.com/px?id=178248&t=1 passed: true,true,true
  url: https://ib.adnxs.com/px?id=178248&t=1 passed: false,false,false
  url: https://ib.adnxs.com/px?id=178248&t=1 passed: false,false,false
  url: https://ib.adnxs.com/px?id=178248&t=1 passed: true,true,true
  url: https://ib.adnxs.com/px?id=178248&t=1 passed: true,true,true
  url: https://ib.adnxs.com/px?id=178248&t=1 passed: true,true,true
  url: https://ib.adnxs.com/px?id=178248&t=1 passed: false,false,false
  url: https://ib.adnxs.com/px?id=178248&t=1 passed: false,false,false,false,false
  url: https://ib.adnxs.com/px?id=178248&t=1 passed: false,false,false
  url: https://ib.adnxs.com/px?id=178248&t=1 passed: false,false,false
  url: https://ib.adnxs.com/px?id=178248&t=1 passed: false,false,false
Bing AdsTests whether the browser blocks the page from loading the tracker at https://bat.bing.com/bat.js
  url: https://bat.bing.com/bat.js passed: true,true,true
  url: https://bat.bing.com/bat.js passed: false,false,false
  url: https://bat.bing.com/bat.js passed: false,false,false
  url: https://bat.bing.com/bat.js passed: false,false,false
  url: https://bat.bing.com/bat.js passed: true,true,true
  url: https://bat.bing.com/bat.js passed: true,true,true
  url: https://bat.bing.com/bat.js passed: false,false,false
  url: https://bat.bing.com/bat.js passed: false,false,false,false,false
  url: https://bat.bing.com/bat.js passed: false,false,false
  url: https://bat.bing.com/bat.js passed: false,false,false
  url: https://bat.bing.com/bat.js passed: false,false,false
ChartbeatTests whether the browser blocks the page from loading the tracker at https://static.chartbeat.com/js/chartbeat.js
  url: https://static.chartbeat.com/js/chartbeat.js passed: true,true,true
  url: https://static.chartbeat.com/js/chartbeat.js passed: false,false,false
  url: https://static.chartbeat.com/js/chartbeat.js passed: false,false,false
  url: https://static.chartbeat.com/js/chartbeat.js passed: true,true,true
  url: https://static.chartbeat.com/js/chartbeat.js passed: true,true,true
  url: https://static.chartbeat.com/js/chartbeat.js passed: true,true,true
  url: https://static.chartbeat.com/js/chartbeat.js passed: false,false,false
  url: https://static.chartbeat.com/js/chartbeat.js passed: false,false,false,false,false
  url: https://static.chartbeat.com/js/chartbeat.js passed: false,false,false
  url: https://static.chartbeat.com/js/chartbeat.js passed: false,false,false
  url: https://static.chartbeat.com/js/chartbeat.js passed: false,false,false
CriteoTests whether the browser blocks the page from loading the tracker at https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx
  url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx passed: true,true,true
  url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx passed: false,false,false
  url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx passed: false,false,false
  url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx passed: true,true,true
  url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx passed: true,true,true
  url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx passed: true,true,true
  url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx passed: false,false,false
  url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx passed: false,false,false,false,false
  url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx passed: false,false,false
  url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx passed: false,false,false
  url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx passed: false,false,false
DoubleClick (Google)Tests whether the browser blocks the page from loading the tracker at https://securepubads.g.doubleclick.net/static/glade.js
  url: https://securepubads.g.doubleclick.net/static/glade.js passed: true,true,true
  url: https://securepubads.g.doubleclick.net/static/glade.js passed: false,false,false
  url: https://securepubads.g.doubleclick.net/static/glade.js passed: false,false,false
  url: https://securepubads.g.doubleclick.net/static/glade.js passed: true,true,true
  url: https://securepubads.g.doubleclick.net/static/glade.js passed: true,true,true
  url: https://securepubads.g.doubleclick.net/static/glade.js passed: true,true,true
  url: https://securepubads.g.doubleclick.net/static/glade.js passed: false,false,false
  url: https://securepubads.g.doubleclick.net/static/glade.js passed: false,false,false,false,false
  url: https://securepubads.g.doubleclick.net/static/glade.js passed: false,false,false
  url: https://securepubads.g.doubleclick.net/static/glade.js passed: false,false,false
  url: https://securepubads.g.doubleclick.net/static/glade.js passed: false,false,false
Facebook trackingTests whether the browser blocks the page from loading the tracker at https://connect.facebook.net/en_US/fbevents.js
  url: https://connect.facebook.net/en_US/fbevents.js passed: true,true,true
  url: https://connect.facebook.net/en_US/fbevents.js passed: false,false,false
  url: https://connect.facebook.net/en_US/fbevents.js passed: false,false,false
  url: https://connect.facebook.net/en_US/fbevents.js passed: true,true,true
  url: https://connect.facebook.net/en_US/fbevents.js passed: true,true,true
  url: https://connect.facebook.net/en_US/fbevents.js passed: true,true,true
  url: https://connect.facebook.net/en_US/fbevents.js passed: false,false,false
  url: https://connect.facebook.net/en_US/fbevents.js passed: false,false,false,false,false
  url: https://connect.facebook.net/en_US/fbevents.js passed: false,false,false
  url: https://connect.facebook.net/en_US/fbevents.js passed: false,false,false
  url: https://connect.facebook.net/en_US/fbevents.js passed: false,false,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/
  url: https://www.google.com/pagead/1p-user-list/ passed: true,true,true
  url: https://www.google.com/pagead/1p-user-list/ passed: false,false,false
  url: https://www.google.com/pagead/1p-user-list/ passed: false,false,false
  url: https://www.google.com/pagead/1p-user-list/ passed: false,false,false
  url: https://www.google.com/pagead/1p-user-list/ passed: true,true,true
  url: https://www.google.com/pagead/1p-user-list/ passed: true,true,true
  url: https://www.google.com/pagead/1p-user-list/ passed: false,false,false
  url: https://www.google.com/pagead/1p-user-list/ passed: false,false,false,false,false
  url: https://www.google.com/pagead/1p-user-list/ passed: false,false,false
  url: https://www.google.com/pagead/1p-user-list/ passed: false,false,false
  url: https://www.google.com/pagead/1p-user-list/ passed: false,false,false
Google AnalyticsTests whether the browser blocks the page from loading the tracker at https://google-analytics.com/urchin.js
  url: https://google-analytics.com/urchin.js passed: true,true,true
  url: https://google-analytics.com/urchin.js passed: false,false,false
  url: https://google-analytics.com/urchin.js passed: false,false,false
  url: https://google-analytics.com/urchin.js passed: true,true,true
  url: https://google-analytics.com/urchin.js passed: true,true,true
  url: https://google-analytics.com/urchin.js passed: true,true,true
  url: https://google-analytics.com/urchin.js passed: false,false,false
  url: https://google-analytics.com/urchin.js passed: false,false,false,false,false
  url: https://google-analytics.com/urchin.js passed: false,false,false
  url: https://google-analytics.com/urchin.js passed: false,false,false
  url: https://google-analytics.com/urchin.js passed: false,false,false
Google Tag ManagerTests whether the browser blocks the page from loading the tracker at https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL
  url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL passed: true,true,true
  url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL passed: false,false,false
  url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL passed: false,false,false
  url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL passed: false,false,false
  url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL passed: true,true,true
  url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL passed: true,true,true
  url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL passed: false,false,false
  url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL passed: false,false,false,false,false
  url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL passed: false,false,false
  url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL passed: false,false,false
  url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL passed: false,false,false
Index ExchangeTests 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
  url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 passed: true,true,true
  url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 passed: false,false,false
  url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 passed: false,false,false
  url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 passed: true,true,true
  url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 passed: true,true,true
  url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 passed: true,true,true
  url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 passed: false,false,false
  url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 passed: false,false,false,false,false
  url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 passed: false,false,false
  url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 passed: false,false,false
  url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 passed: false,false,false
New RelicTests whether the browser blocks the page from loading the tracker at https://js-agent.newrelic.com/nr-1212.min.js
  url: https://js-agent.newrelic.com/nr-1212.min.js passed: true,true,true
  url: https://js-agent.newrelic.com/nr-1212.min.js passed: false,false,false
  url: https://js-agent.newrelic.com/nr-1212.min.js passed: false,false,false
  url: https://js-agent.newrelic.com/nr-1212.min.js passed: true,true,true
  url: https://js-agent.newrelic.com/nr-1212.min.js passed: true,true,true
  url: https://js-agent.newrelic.com/nr-1212.min.js passed: true,true,true
  url: https://js-agent.newrelic.com/nr-1212.min.js passed: false,false,false
  url: https://js-agent.newrelic.com/nr-1212.min.js passed: false,false,false,false,false
  url: https://js-agent.newrelic.com/nr-1212.min.js passed: false,false,false
  url: https://js-agent.newrelic.com/nr-1212.min.js passed: false,false,false
  url: https://js-agent.newrelic.com/nr-1212.min.js passed: false,false,false
QuantcastTests whether the browser blocks the page from loading the tracker at https://pixel.quantserve.com/pixel
  url: https://pixel.quantserve.com/pixel passed: true,true,true
  url: https://pixel.quantserve.com/pixel passed: false,false,false
  url: https://pixel.quantserve.com/pixel passed: false,false,false
  url: https://pixel.quantserve.com/pixel passed: true,true,true
  url: https://pixel.quantserve.com/pixel passed: true,true,true
  url: https://pixel.quantserve.com/pixel passed: true,true,true
  url: https://pixel.quantserve.com/pixel passed: false,false,false
  url: https://pixel.quantserve.com/pixel passed: false,false,false,false,false
  url: https://pixel.quantserve.com/pixel passed: false,false,false
  url: https://pixel.quantserve.com/pixel passed: false,false,false
  url: https://pixel.quantserve.com/pixel passed: false,false,false
Scorecard Research BeaconTests whether the browser blocks the page from loading the tracker at https://sb.scorecardresearch.com/internal-c2/default/cs.js
  url: https://sb.scorecardresearch.com/internal-c2/default/cs.js passed: true,true,true
  url: https://sb.scorecardresearch.com/internal-c2/default/cs.js passed: false,false,false
  url: https://sb.scorecardresearch.com/internal-c2/default/cs.js passed: false,false,false
  url: https://sb.scorecardresearch.com/internal-c2/default/cs.js passed: true,true,true
  url: https://sb.scorecardresearch.com/internal-c2/default/cs.js passed: true,true,true
  url: https://sb.scorecardresearch.com/internal-c2/default/cs.js passed: true,true,true
  url: https://sb.scorecardresearch.com/internal-c2/default/cs.js passed: false,false,false
  url: https://sb.scorecardresearch.com/internal-c2/default/cs.js passed: false,false,false,false,false
  url: https://sb.scorecardresearch.com/internal-c2/default/cs.js passed: false,false,false
  url: https://sb.scorecardresearch.com/internal-c2/default/cs.js passed: false,false,false
  url: https://sb.scorecardresearch.com/internal-c2/default/cs.js passed: false,false,false
TaboolaTests whether the browser blocks the page from loading the tracker at https://trc.taboola.com/futureplc-tomsguide/trc/3/json
  url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json passed: true,true,true
  url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json passed: false,false,false
  url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json passed: false,false,false
  url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json passed: true,true,true
  url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json passed: true,true,true
  url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json passed: true,true,true
  url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json passed: false,false,false
  url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json passed: false,false,false,false,false
  url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json passed: false,false,false
  url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json passed: false,false,false
  url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json passed: false,false,false
Twitter pixelTests whether the browser blocks the page from loading the tracker at https://t.co/i/adsct
  url: https://t.co/i/adsct passed: true,true,true
  url: https://t.co/i/adsct passed: false,false,false
  url: https://t.co/i/adsct passed: false,false,false
  url: https://t.co/i/adsct passed: true,true,true
  url: https://t.co/i/adsct passed: true,true,true
  url: https://t.co/i/adsct passed: true,true,true
  url: https://t.co/i/adsct passed: false,false,false
  url: https://t.co/i/adsct passed: false,false,false,false,false
  url: https://t.co/i/adsct passed: false,false,false
  url: https://t.co/i/adsct passed: false,false,false
  url: https://t.co/i/adsct passed: false,false,false
Yandex AdsTests whether the browser blocks the page from loading the tracker at https://yandex.ru/ads/system/header-bidding.js
  url: https://yandex.ru/ads/system/header-bidding.js passed: true,true,true
  url: https://yandex.ru/ads/system/header-bidding.js passed: false,false,false
  url: https://yandex.ru/ads/system/header-bidding.js passed: false,false,false
  url: https://yandex.ru/ads/system/header-bidding.js passed: false,false,false
  url: https://yandex.ru/ads/system/header-bidding.js passed: true,true,true
  url: https://yandex.ru/ads/system/header-bidding.js passed: true,true,true
  url: https://yandex.ru/ads/system/header-bidding.js passed: false,false,false
  url: https://yandex.ru/ads/system/header-bidding.js passed: false,false,false,false,false
  url: https://yandex.ru/ads/system/header-bidding.js passed: false,false,false
  url: https://yandex.ru/ads/system/header-bidding.js passed: false,false,false
  url: https://yandex.ru/ads/system/header-bidding.js passed: false,false,false
Tracking cookie protection tests Which browsers block important known tracking cookies?
A large fraction of web pages on the web have hidden third-party trackers that read and write cookies in your browser. These cookies can be used to track your browsing across websites. This section checks to see if a browser stops cross-site tracking by cookies from 20 of the largest trackers listed by https://whotracks.me.`,
AdobeTests whether the browser stops cookies from munchkin.marketo.net from tracking users across websites.
  passed: true,true,true url: https://munchkin.marketo.net/munchkin.js cookieFound: false,false,false
  passed: true,true,true url: https://munchkin.marketo.net/munchkin.js cookieFound: false,false,false
  passed: true,true,true url: https://munchkin.marketo.net/munchkin.js cookieFound: false,false,false
  passed: true,true,true url: https://munchkin.marketo.net/munchkin.js cookieFound: false,false,false
  passed: true,true,true url: https://munchkin.marketo.net/munchkin.js cookieFound: false,false,false
  passed: true,true,true url: https://munchkin.marketo.net/munchkin.js cookieFound: false,false,false
  passed: true,true,true url: https://munchkin.marketo.net/munchkin.js cookieFound: false,false,false
  passed: true,true,true,true,true url: https://munchkin.marketo.net/munchkin.js cookieFound: false,false,false,false,false
  passed: true,true,true url: https://munchkin.marketo.net/munchkin.js cookieFound: false,false,false
  passed: true,true,true url: https://munchkin.marketo.net/munchkin.js cookieFound: false,false,false
  passed: true,true,true url: https://munchkin.marketo.net/munchkin.js cookieFound: false,false,false
Adobe Audience ManagerTests whether the browser stops cookies from dpm.demdex.net from tracking users across websites.
  passed: true,true,true url: https://dpm.demdex.net/ibs cookieFound: false,false,false
  passed: true,true,true url: https://dpm.demdex.net/ibs cookieFound: false,false,false
  passed: true,true,true url: https://dpm.demdex.net/ibs cookieFound: false,false,false
  passed: true,true,true url: https://dpm.demdex.net/ibs cookieFound: false,false,false
  passed: true,true,true url: https://dpm.demdex.net/ibs cookieFound: false,false,false
  passed: true,true,true url: https://dpm.demdex.net/ibs cookieFound: false,false,false
  passed: true,true,true url: https://dpm.demdex.net/ibs cookieFound: false,false,false
  passed: true,true,true,true,true url: https://dpm.demdex.net/ibs cookieFound: false,false,false,false,false
  passed: true,true,true url: https://dpm.demdex.net/ibs cookieFound: false,false,false
  passed: true,true,true url: https://dpm.demdex.net/ibs cookieFound: false,false,false
  passed: true,true,true url: https://dpm.demdex.net/ibs cookieFound: false,false,false
Amazon adsystemTests whether the browser stops cookies from s.amazon-adsystem.com from tracking users across websites.
  passed: true,true,true url: https://s.amazon-adsystem.com/dcm cookieFound: false,false,false
  passed: true,true,true url: https://s.amazon-adsystem.com/dcm cookieFound: false,false,false
  passed: true,true,true url: https://s.amazon-adsystem.com/dcm cookieFound: false,false,false
  passed: true,true,true url: https://s.amazon-adsystem.com/dcm cookieFound: false,false,false
  passed: true,true,true url: https://s.amazon-adsystem.com/dcm cookieFound: false,false,false
  passed: true,true,true url: https://s.amazon-adsystem.com/dcm cookieFound: false,false,false
  passed: true,true,true url: https://s.amazon-adsystem.com/dcm cookieFound: false,false,false
  passed: true,true,true,true,true url: https://s.amazon-adsystem.com/dcm cookieFound: false,false,false,false,false
  passed: true,true,true url: https://s.amazon-adsystem.com/dcm cookieFound: false,false,false
  passed: true,true,true url: https://s.amazon-adsystem.com/dcm cookieFound: false,false,false
  passed: true,true,true url: https://s.amazon-adsystem.com/dcm cookieFound: false,false,false
AppNexusTests whether the browser stops cookies from ib.adnxs.com from tracking users across websites.
  passed: true,true,true url: https://ib.adnxs.com/px?id=178248&t=1 cookieFound: false,false,false
  passed: true,true,true url: https://ib.adnxs.com/px?id=178248&t=1 cookieFound: false,false,false
  passed: true,true,true url: https://ib.adnxs.com/px?id=178248&t=1 cookieFound: false,false,false
  passed: true,true,true url: https://ib.adnxs.com/px?id=178248&t=1 cookieFound: false,false,false
  passed: true,true,true url: https://ib.adnxs.com/px?id=178248&t=1 cookieFound: false,false,false
  passed: true,true,true url: https://ib.adnxs.com/px?id=178248&t=1 cookieFound: false,false,false
  passed: true,true,true url: https://ib.adnxs.com/px?id=178248&t=1 cookieFound: false,false,false
  passed: true,true,true,true,true url: https://ib.adnxs.com/px?id=178248&t=1 cookieFound: false,false,false,false,false
  passed: true,true,true url: https://ib.adnxs.com/px?id=178248&t=1 cookieFound: false,false,false
  passed: true,true,true url: https://ib.adnxs.com/px?id=178248&t=1 cookieFound: false,false,false
  passed: true,true,true url: https://ib.adnxs.com/px?id=178248&t=1 cookieFound: false,false,false
Bing AdsTests whether the browser stops cookies from bat.bing.com from tracking users across websites.
  passed: true,true,true url: https://bat.bing.com/bat.js cookieFound: false,false,false
  passed: true,true,true url: https://bat.bing.com/bat.js cookieFound: false,false,false
  passed: true,true,true url: https://bat.bing.com/bat.js cookieFound: false,false,false
  passed: true,true,true url: https://bat.bing.com/bat.js cookieFound: false,false,false
  passed: true,true,true url: https://bat.bing.com/bat.js cookieFound: false,false,false
  passed: true,true,true url: https://bat.bing.com/bat.js cookieFound: false,false,false
  passed: true,true,true url: https://bat.bing.com/bat.js cookieFound: false,false,false
  passed: true,true,true,true,true url: https://bat.bing.com/bat.js cookieFound: false,false,false,false,false
  passed: true,true,true url: https://bat.bing.com/bat.js cookieFound: false,false,false
  passed: true,true,true url: https://bat.bing.com/bat.js cookieFound: false,false,false
  passed: true,true,true url: https://bat.bing.com/bat.js cookieFound: false,false,false
ChartbeatTests whether the browser stops cookies from static.chartbeat.com from tracking users across websites.
  passed: true,true,true url: https://static.chartbeat.com/js/chartbeat.js cookieFound: false,false,false
  passed: true,true,true url: https://static.chartbeat.com/js/chartbeat.js cookieFound: false,false,false
  passed: false,false,false url: https://static.chartbeat.com/js/chartbeat.js cookieFound: true,true,true
  passed: true,true,true url: https://static.chartbeat.com/js/chartbeat.js cookieFound: false,false,false
  passed: true,true,true url: https://static.chartbeat.com/js/chartbeat.js cookieFound: false,false,false
  passed: true,true,true url: https://static.chartbeat.com/js/chartbeat.js cookieFound: false,false,false
  passed: true,true,true url: https://static.chartbeat.com/js/chartbeat.js cookieFound: false,false,false
  passed: true,true,true,true,true url: https://static.chartbeat.com/js/chartbeat.js cookieFound: false,false,false,false,false
  passed: true,true,true url: https://static.chartbeat.com/js/chartbeat.js cookieFound: false,false,false
  passed: true,true,true url: https://static.chartbeat.com/js/chartbeat.js cookieFound: false,false,false
  passed: true,true,true url: https://static.chartbeat.com/js/chartbeat.js cookieFound: false,false,false
CriteoTests whether the browser stops cookies from dis.criteo.com from tracking users across websites.
  passed: true,true,true url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx cookieFound: false,false,false
  passed: true,true,true url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx cookieFound: false,false,false
  passed: true,true,true url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx cookieFound: false,false,false
  passed: true,true,true url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx cookieFound: false,false,false
  passed: true,true,true url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx cookieFound: false,false,false
  passed: true,true,true url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx cookieFound: false,false,false
  passed: true,true,true url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx cookieFound: false,false,false
  passed: true,true,true,true,true url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx cookieFound: false,false,false,false,false
  passed: true,true,true url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx cookieFound: false,false,false
  passed: true,true,true url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx cookieFound: false,false,false
  passed: true,true,true url: https://dis.criteo.com/dis/rtb/appnexus/cookiematch.aspx cookieFound: false,false,false
DoubleClick (Google)Tests whether the browser stops cookies from securepubads.g.doubleclick.net from tracking users across websites.
  passed: true,true,true url: https://securepubads.g.doubleclick.net/static/glade.js cookieFound: false,false,false
  passed: true,true,true url: https://securepubads.g.doubleclick.net/static/glade.js cookieFound: false,false,false
  passed: true,true,true url: https://securepubads.g.doubleclick.net/static/glade.js cookieFound: false,false,false
  passed: true,true,true url: https://securepubads.g.doubleclick.net/static/glade.js cookieFound: false,false,false
  passed: true,true,true url: https://securepubads.g.doubleclick.net/static/glade.js cookieFound: false,false,false
  passed: true,true,true url: https://securepubads.g.doubleclick.net/static/glade.js cookieFound: false,false,false
  passed: true,true,true url: https://securepubads.g.doubleclick.net/static/glade.js cookieFound: false,false,false
  passed: true,true,true,true,true url: https://securepubads.g.doubleclick.net/static/glade.js cookieFound: false,false,false,false,false
  passed: true,true,true url: https://securepubads.g.doubleclick.net/static/glade.js cookieFound: false,false,false
  passed: true,true,true url: https://securepubads.g.doubleclick.net/static/glade.js cookieFound: false,false,false
  passed: true,true,true url: https://securepubads.g.doubleclick.net/static/glade.js cookieFound: false,false,false
Facebook trackingTests whether the browser stops cookies from connect.facebook.net from tracking users across websites.
  passed: true,true,true url: https://connect.facebook.net/en_US/fbevents.js cookieFound: false,false,false
  passed: true,true,true url: https://connect.facebook.net/en_US/fbevents.js cookieFound: false,false,false
  passed: true,true,true url: https://connect.facebook.net/en_US/fbevents.js cookieFound: false,false,false
  passed: true,true,true url: https://connect.facebook.net/en_US/fbevents.js cookieFound: false,false,false
  passed: true,true,true url: https://connect.facebook.net/en_US/fbevents.js cookieFound: false,false,false
  passed: true,true,true url: https://connect.facebook.net/en_US/fbevents.js cookieFound: false,false,false
  passed: true,true,true url: https://connect.facebook.net/en_US/fbevents.js cookieFound: false,false,false
  passed: true,true,true,true,true url: https://connect.facebook.net/en_US/fbevents.js cookieFound: false,false,false,false,false
  passed: true,true,true url: https://connect.facebook.net/en_US/fbevents.js cookieFound: false,false,false
  passed: true,true,true url: https://connect.facebook.net/en_US/fbevents.js cookieFound: false,false,false
  passed: true,true,true url: https://connect.facebook.net/en_US/fbevents.js cookieFound: false,false,false
Google (third-party ad pixel)Tests whether the browser stops cookies from www.google.com from tracking users across websites.
  passed: true,true,true url: https://www.google.com/pagead/1p-user-list/ cookieFound: false,false,false
  passed: true,true,true url: https://www.google.com/pagead/1p-user-list/ cookieFound: false,false,false
  passed: true,true,true url: https://www.google.com/pagead/1p-user-list/ cookieFound: false,false,false
  passed: true,true,true url: https://www.google.com/pagead/1p-user-list/ cookieFound: false,false,false
  passed: true,true,true url: https://www.google.com/pagead/1p-user-list/ cookieFound: false,false,false
  passed: true,true,true url: https://www.google.com/pagead/1p-user-list/ cookieFound: false,false,false
  passed: true,true,true url: https://www.google.com/pagead/1p-user-list/ cookieFound: false,false,false
  passed: true,true,true,true,true url: https://www.google.com/pagead/1p-user-list/ cookieFound: false,false,false,false,false
  passed: true,true,true url: https://www.google.com/pagead/1p-user-list/ cookieFound: false,false,false
  passed: true,true,true url: https://www.google.com/pagead/1p-user-list/ cookieFound: false,false,false
  passed: true,true,true url: https://www.google.com/pagead/1p-user-list/ cookieFound: false,false,false
Google AnalyticsTests whether the browser stops cookies from google-analytics.com from tracking users across websites.
  passed: true,true,true url: https://google-analytics.com/urchin.js cookieFound: false,false,false
  passed: true,true,true url: https://google-analytics.com/urchin.js cookieFound: false,false,false
  passed: false,false,false url: https://google-analytics.com/urchin.js cookieFound: true,true,true
  passed: true,true,true url: https://google-analytics.com/urchin.js cookieFound: false,false,false
  passed: true,true,true url: https://google-analytics.com/urchin.js cookieFound: false,false,false
  passed: true,true,true url: https://google-analytics.com/urchin.js cookieFound: false,false,false
  passed: true,true,true url: https://google-analytics.com/urchin.js cookieFound: false,false,false
  passed: true,true,true,true,true url: https://google-analytics.com/urchin.js cookieFound: false,false,false,false,false
  passed: true,true,true url: https://google-analytics.com/urchin.js cookieFound: false,false,false
  passed: true,true,true url: https://google-analytics.com/urchin.js cookieFound: false,false,false
  passed: true,true,true url: https://google-analytics.com/urchin.js cookieFound: false,false,false
Google Tag ManagerTests whether the browser stops cookies from www.googletagmanager.com from tracking users across websites.
  passed: true,true,true url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL cookieFound: false,false,false
  passed: true,true,true url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL cookieFound: false,false,false
  passed: false,false,false url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL cookieFound: true,true,true
  passed: true,true,true url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL cookieFound: false,false,false
  passed: true,true,true url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL cookieFound: false,false,false
  passed: true,true,true url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL cookieFound: false,false,false
  passed: true,true,true url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL cookieFound: false,false,false
  passed: true,true,true,true,true url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL cookieFound: false,false,false,false,false
  passed: true,true,true url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL cookieFound: false,false,false
  passed: true,true,true url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL cookieFound: false,false,false
  passed: true,true,true url: https://www.googletagmanager.com/gtag.js?id=GTM-NX4SMZL cookieFound: false,false,false
Index ExchangeTests whether the browser stops cookies from dsum-sec.casalemedia.com from tracking users across websites.
  passed: true,true,true url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 cookieFound: false,false,false
  passed: true,true,true url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 cookieFound: false,false,false
  passed: true,true,true url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 cookieFound: false,false,false
  passed: true,true,true url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 cookieFound: false,false,false
  passed: true,true,true url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 cookieFound: false,false,false
  passed: true,true,true url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 cookieFound: false,false,false
  passed: true,true,true url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 cookieFound: false,false,false
  passed: true,true,true,true,true url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 cookieFound: false,false,false,false,false
  passed: true,true,true url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 cookieFound: false,false,false
  passed: true,true,true url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 cookieFound: false,false,false
  passed: true,true,true url: https://dsum-sec.casalemedia.com/crum?cm_dsp_id=10&external_user_id=629685505537&C=1 cookieFound: false,false,false
New RelicTests whether the browser stops cookies from js-agent.newrelic.com from tracking users across websites.
  passed: true,true,true url: https://js-agent.newrelic.com/nr-1212.min.js cookieFound: false,false,false
  passed: true,true,true url: https://js-agent.newrelic.com/nr-1212.min.js cookieFound: false,false,false
  passed: false,false,false url: https://js-agent.newrelic.com/nr-1212.min.js cookieFound: true,true,true
  passed: true,true,true url: https://js-agent.newrelic.com/nr-1212.min.js cookieFound: false,false,false
  passed: true,true,true url: https://js-agent.newrelic.com/nr-1212.min.js cookieFound: false,false,false
  passed: true,true,true url: https://js-agent.newrelic.com/nr-1212.min.js cookieFound: false,false,false
  passed: true,true,true url: https://js-agent.newrelic.com/nr-1212.min.js cookieFound: false,false,false
  passed: true,true,true,true,true url: https://js-agent.newrelic.com/nr-1212.min.js cookieFound: false,false,false,false,false
  passed: true,true,true url: https://js-agent.newrelic.com/nr-1212.min.js cookieFound: false,false,false
  passed: true,true,true url: https://js-agent.newrelic.com/nr-1212.min.js cookieFound: false,false,false
  passed: true,true,true url: https://js-agent.newrelic.com/nr-1212.min.js cookieFound: false,false,false
QuantcastTests whether the browser stops cookies from pixel.quantserve.com from tracking users across websites.
  passed: true,true,true url: https://pixel.quantserve.com/pixel cookieFound: false,false,false
  passed: true,true,true url: https://pixel.quantserve.com/pixel cookieFound: false,false,false
  passed: true,true,true url: https://pixel.quantserve.com/pixel cookieFound: false,false,false
  passed: true,true,true url: https://pixel.quantserve.com/pixel cookieFound: false,false,false
  passed: true,true,true url: https://pixel.quantserve.com/pixel cookieFound: false,false,false
  passed: true,true,true url: https://pixel.quantserve.com/pixel cookieFound: false,false,false
  passed: true,true,true url: https://pixel.quantserve.com/pixel cookieFound: false,false,false
  passed: true,true,true,true,true url: https://pixel.quantserve.com/pixel cookieFound: false,false,false,false,false
  passed: true,true,true url: https://pixel.quantserve.com/pixel cookieFound: false,false,false
  passed: true,true,true url: https://pixel.quantserve.com/pixel cookieFound: false,false,false
  passed: true,true,true url: https://pixel.quantserve.com/pixel cookieFound: false,false,false
Scorecard Research BeaconTests whether the browser stops cookies from sb.scorecardresearch.com from tracking users across websites.
  passed: true,true,true url: https://sb.scorecardresearch.com/internal-c2/default/cs.js cookieFound: false,false,false
  passed: true,true,true url: https://sb.scorecardresearch.com/internal-c2/default/cs.js cookieFound: false,false,false
  passed: false,false,false url: https://sb.scorecardresearch.com/internal-c2/default/cs.js cookieFound: true,true,true
  passed: true,true,true url: https://sb.scorecardresearch.com/internal-c2/default/cs.js cookieFound: false,false,false
  passed: true,true,true url: https://sb.scorecardresearch.com/internal-c2/default/cs.js cookieFound: false,false,false
  passed: true,true,true url: https://sb.scorecardresearch.com/internal-c2/default/cs.js cookieFound: false,false,false
  passed: true,true,true url: https://sb.scorecardresearch.com/internal-c2/default/cs.js cookieFound: false,false,false
  passed: true,true,true,true,true url: https://sb.scorecardresearch.com/internal-c2/default/cs.js cookieFound: false,false,false,false,false
  passed: true,true,true url: https://sb.scorecardresearch.com/internal-c2/default/cs.js cookieFound: false,false,false
  passed: true,true,true url: https://sb.scorecardresearch.com/internal-c2/default/cs.js cookieFound: false,false,false
  passed: true,true,true url: https://sb.scorecardresearch.com/internal-c2/default/cs.js cookieFound: false,false,false
TaboolaTests whether the browser stops cookies from trc.taboola.com from tracking users across websites.
  passed: true,true,true url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json cookieFound: false,false,false
  passed: true,true,true url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json cookieFound: false,false,false
  passed: true,true,true url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json cookieFound: false,false,false
  passed: true,true,true url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json cookieFound: false,false,false
  passed: true,true,true url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json cookieFound: false,false,false
  passed: true,true,true url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json cookieFound: false,false,false
  passed: true,true,true url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json cookieFound: false,false,false
  passed: true,true,true,true,true url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json cookieFound: false,false,false,false,false
  passed: true,true,true url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json cookieFound: false,false,false
  passed: true,true,true url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json cookieFound: false,false,false
  passed: true,true,true url: https://trc.taboola.com/futureplc-tomsguide/trc/3/json cookieFound: false,false,false
Twitter pixelTests whether the browser stops cookies from t.co from tracking users across websites.
  passed: true,true,true url: https://t.co/i/adsct cookieFound: false,false,false
  passed: true,true,true url: https://t.co/i/adsct cookieFound: false,false,false
  passed: false,false,false url: https://t.co/i/adsct cookieFound: true,true,true
  passed: true,true,true url: https://t.co/i/adsct cookieFound: false,false,false
  passed: true,true,true url: https://t.co/i/adsct cookieFound: false,false,false
  passed: true,true,true url: https://t.co/i/adsct cookieFound: false,false,false
  passed: true,true,true url: https://t.co/i/adsct cookieFound: false,false,false
  passed: true,true,true,true,true url: https://t.co/i/adsct cookieFound: false,false,false,false,false
  passed: true,true,true url: https://t.co/i/adsct cookieFound: false,false,false
  passed: true,true,true url: https://t.co/i/adsct cookieFound: false,false,false
  passed: true,true,true url: https://t.co/i/adsct cookieFound: false,false,false
Yandex AdsTests whether the browser stops cookies from yandex.ru from tracking users across websites.
  passed: true,true,true url: https://yandex.ru/ads/system/header-bidding.js cookieFound: false,false,false
  passed: true,true,true url: https://yandex.ru/ads/system/header-bidding.js cookieFound: false,false,false
  passed: true,true,true url: https://yandex.ru/ads/system/header-bidding.js cookieFound: false,false,false
  passed: true,true,true url: https://yandex.ru/ads/system/header-bidding.js cookieFound: false,false,false
  passed: true,true,true url: https://yandex.ru/ads/system/header-bidding.js cookieFound: false,false,false
  passed: true,true,true url: https://yandex.ru/ads/system/header-bidding.js cookieFound: false,false,false
  passed: true,true,true url: https://yandex.ru/ads/system/header-bidding.js cookieFound: false,false,false
  passed: true,true,true,true,true url: https://yandex.ru/ads/system/header-bidding.js cookieFound: false,false,false,false,false
  passed: true,true,true url: https://yandex.ru/ads/system/header-bidding.js cookieFound: false,false,false
  passed: true,true,true url: https://yandex.ru/ads/system/header-bidding.js cookieFound: false,false,false
  passed: true,true,true url: https://yandex.ru/ads/system/header-bidding.js cookieFound: false,false,false
Cross-session first-party tracking tests Which 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-SvcAlt-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.
  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, h3, h3 result, different session: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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, h3, h3 result, different session: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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, h3, h3 result, different session: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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, h3, h3 result, different session: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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, h3, h3 result, different session: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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, h3, h3 result, different session: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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, h3, h3 result, different session: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
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
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 result, different session: h2, h2, h2 unsupported: true, true, true passed: undefined test failed: false, false, false
  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, h3, h3 result, different session: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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, h3, h3 result, different session: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
CacheStorageThe 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.
  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: 5465a603-de27-44f5-b8c4-707bfb613e2e_1p, 78421fc4-bf96-4cca-890a-80da7897dc6d_1p, 80b14108-7165-4df7-a9e6-ff02143416a6_1p result, different session: Error: Cannot read properties of undefined (reading 'url'), Error: Cannot read properties of undefined (reading 'url'), Error: Cannot read properties of undefined (reading 'url') unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${key}`]); } catch (e) { throw new Error("Unsupported"); } } read: async () => { let cache = await caches.open("supercookies"); let cacheKeys = await cache.keys(); let url = cacheKeys[0].url; return (new URL(url)).searchParams.get("key"); } result, same session: 716abdfe-395d-427a-95f5-86b590a83dbe_1p, 74b40c1c-a56c-422c-8ec2-977bc24c84e1_1p, a1abfa62-2197-4ef7-a6aa-1649c66a9829_1p result, different session: Error: Cannot read properties of undefined (reading 'url'), Error: Cannot read properties of undefined (reading 'url'), Error: Cannot read properties of undefined (reading 'url') unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${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: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a_1p, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51_1p, 0e22765a-3b45-4d4f-96e1-155b36d72016_1p result, different session: Error: Cannot read properties of undefined (reading 'url'), Error: Cannot read properties of undefined (reading 'url'), Error: Cannot read properties of undefined (reading 'url') unsupported: false, false, false passed: true, true, true test failed: false, false, false
write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${key}`]); } catch (e) { throw new Error("Unsupported"); } } read: async () => { let cache = await caches.open("supercookies"); let cacheKeys = await cache.keys(); let url = cacheKeys[0].url; return (new URL(url)).searchParams.get("key"); } result, same session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. result, different session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${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: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. result, different session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${key}`]); } catch (e) { throw new Error("Unsupported"); } } read: async () => { let cache = await caches.open("supercookies"); let cacheKeys = await cache.keys(); let url = cacheKeys[0].url; return (new URL(url)).searchParams.get("key"); } result, same session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. result, different session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: true, true, true passed: undefined test failed: false, false, false
  write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${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: c28bfb99-bfe7-484e-91ee-401936368f8e_1p, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6_1p, 41f02047-71ab-44db-a34c-341407f5d677_1p result, different session: Error: Cannot read properties of undefined (reading 'url'), Error: Cannot read properties of undefined (reading 'url'), Error: Cannot read properties of undefined (reading 'url') unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${key}`]); } catch (e) { throw new Error("Unsupported"); } } read: async () => { let cache = await caches.open("supercookies"); let cacheKeys = await cache.keys(); let url = cacheKeys[0].url; return (new URL(url)).searchParams.get("key"); } result, same session: 07fc3252-9841-4d6b-bedd-60addf28555e_1p, 07fc3252-9841-4d6b-bedd-60addf28555e_1p, 07fc3252-9841-4d6b-bedd-60addf28555e_1p, 07fc3252-9841-4d6b-bedd-60addf28555e_1p, 07fc3252-9841-4d6b-bedd-60addf28555e_1p result, different session: 07fc3252-9841-4d6b-bedd-60addf28555e_1p, 07fc3252-9841-4d6b-bedd-60addf28555e_1p, 07fc3252-9841-4d6b-bedd-60addf28555e_1p, 07fc3252-9841-4d6b-bedd-60addf28555e_1p, 07fc3252-9841-4d6b-bedd-60addf28555e_1p unsupported: false, false, false, false, false passed: false, false, false, false, false test failed: false, false, false, false, false
write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${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: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. result, different session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: true, true, true passed: undefined test failed: false, false, false
  write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${key}`]); } catch (e) { throw new Error("Unsupported"); } } read: async () => { let cache = await caches.open("supercookies"); let cacheKeys = await cache.keys(); let url = cacheKeys[0].url; return (new URL(url)).searchParams.get("key"); } result, same session: 48c217f0-1bef-4ff9-a86a-e02c452b3090_1p, 52225fb2-48b7-4a6d-8cba-f85356406aba_1p, 5616596f-2317-42fc-bd3f-f8e6bc122d3e_1p result, different session: Error: Cannot read properties of undefined (reading 'url'), Error: Cannot read properties of undefined (reading 'url'), Error: Cannot read properties of undefined (reading 'url') unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${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: a5be31f4-aa0a-4843-923b-3c4f83f5a928_1p, e31de4a2-0c0c-4125-b3cc-46d11e5579f9_1p, 8db17cd7-36fc-475c-8d65-e14f8da75dc6_1p result, different session: Error: Cannot read properties of undefined (reading 'url'), Error: Cannot read properties of undefined (reading 'url'), Error: Cannot read properties of undefined (reading 'url') unsupported: false, false, false passed: true, true, true test failed: false, false, 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.
  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(`${baseURI}headers`); let cookie = (await response.json())["cookie"]; return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null; } result, same session: 5465a603-de27-44f5-b8c4-707bfb613e2e_1p_http, 78421fc4-bf96-4cca-890a-80da7897dc6d_1p_http, 80b14108-7165-4df7-a9e6-ff02143416a6_1p_http result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value. await fetch(`${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: 716abdfe-395d-427a-95f5-86b590a83dbe_1p_http, 74b40c1c-a56c-422c-8ec2-977bc24c84e1_1p_http, a1abfa62-2197-4ef7-a6aa-1649c66a9829_1p_http result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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(`${baseURI}headers`); let cookie = (await response.json())["cookie"]; return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null; } result, same session: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a_1p_http, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51_1p_http, 0e22765a-3b45-4d4f-96e1-155b36d72016_1p_http result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value. await fetch(`${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: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4_1p_http, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826_1p_http, cf35c52d-e97f-4820-82eb-d8054844f2c1_1p_http result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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(`${baseURI}headers`); let cookie = (await response.json())["cookie"]; return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null; } result, same session: e37747b4-8740-49ba-9270-601151aaf726_1p_http, e2e870e7-134c-4209-b335-78130b0eb740_1p_http, af1f42ee-1067-499d-8093-d4d19b5c49a6_1p_http result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value. await fetch(`${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: b71a2d50-2167-4614-a844-3de0e93814fb_1p_http, 87735b1f-b9af-4abe-8b23-8eb0096d3907_1p_http, e9f1e434-9ee8-4cdb-b17e-75370f35bfa9_1p_http result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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(`${baseURI}headers`); let cookie = (await response.json())["cookie"]; return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null; } result, same session: c28bfb99-bfe7-484e-91ee-401936368f8e_1p_http, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6_1p_http, 41f02047-71ab-44db-a34c-341407f5d677_1p_http result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value. await fetch(`${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: c24314e8-1afc-4d9a-96a4-bc75e5d99b58_1p_http, aa3c8308-259e-464e-aa4f-6e3b827d137c_1p_http, 358e00ee-1af1-443e-8d23-1fa8923e03fc_1p_http, 7fe8a160-092e-4a52-81cd-841a2600cf16_1p_http, cafc6b09-49db-407e-950e-bab9a6e60e9f_1p_http result, different session: c24314e8-1afc-4d9a-96a4-bc75e5d99b58_1p_http, aa3c8308-259e-464e-aa4f-6e3b827d137c_1p_http, 358e00ee-1af1-443e-8d23-1fa8923e03fc_1p_http, 7fe8a160-092e-4a52-81cd-841a2600cf16_1p_http, cafc6b09-49db-407e-950e-bab9a6e60e9f_1p_http unsupported: false, false, false, false, false passed: false, false, false, false, false test failed: false, false, false, false, false
  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(`${baseURI}headers`); let cookie = (await response.json())["cookie"]; return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null; } result, same session: 91977509-fee5-471e-9ccb-9dd38fc58a67_1p_http, aab3ddfd-726f-4857-83c6-8d44ea5e6bb4_1p_http, 43c85c36-872d-485b-852e-5b322a7c7d45_1p_http result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value. await fetch(`${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: 48c217f0-1bef-4ff9-a86a-e02c452b3090_1p_http, 52225fb2-48b7-4a6d-8cba-f85356406aba_1p_http, 5616596f-2317-42fc-bd3f-f8e6bc122d3e_1p_http result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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(`${baseURI}headers`); let cookie = (await response.json())["cookie"]; return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null; } result, same session: a5be31f4-aa0a-4843-923b-3c4f83f5a928_1p_http, e31de4a2-0c0c-4125-b3cc-46d11e5579f9_1p_http, 8db17cd7-36fc-475c-8d65-e14f8da75dc6_1p_http result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
cookie (JS)The cookie, first introduced by Netscape in 1994, is a small amount of data stored by your browser on a website's behalf. It has legitimate uses, but it is also the classic cross-site tracking mechanism, and today still the most popular method of tracking users across websites. Browsers can stop cookies from being used for cross-site tracking by either blocking or partitioning them.
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same session: 5465a603-de27-44f5-b8c4-707bfb613e2e_1p_js, 78421fc4-bf96-4cca-890a-80da7897dc6d_1p_js, 80b14108-7165-4df7-a9e6-ff02143416a6_1p_js result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same session: 716abdfe-395d-427a-95f5-86b590a83dbe_1p_js, 74b40c1c-a56c-422c-8ec2-977bc24c84e1_1p_js, a1abfa62-2197-4ef7-a6aa-1649c66a9829_1p_js result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same session: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a_1p_js, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51_1p_js, 0e22765a-3b45-4d4f-96e1-155b36d72016_1p_js result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same session: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4_1p_js, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826_1p_js, cf35c52d-e97f-4820-82eb-d8054844f2c1_1p_js result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same session: e37747b4-8740-49ba-9270-601151aaf726_1p_js, e2e870e7-134c-4209-b335-78130b0eb740_1p_js, af1f42ee-1067-499d-8093-d4d19b5c49a6_1p_js result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same session: b71a2d50-2167-4614-a844-3de0e93814fb_1p_js, 87735b1f-b9af-4abe-8b23-8eb0096d3907_1p_js, e9f1e434-9ee8-4cdb-b17e-75370f35bfa9_1p_js result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same session: c28bfb99-bfe7-484e-91ee-401936368f8e_1p_js, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6_1p_js, 41f02047-71ab-44db-a34c-341407f5d677_1p_js result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same session: c24314e8-1afc-4d9a-96a4-bc75e5d99b58_1p_js, aa3c8308-259e-464e-aa4f-6e3b827d137c_1p_js, 358e00ee-1af1-443e-8d23-1fa8923e03fc_1p_js, 7fe8a160-092e-4a52-81cd-841a2600cf16_1p_js, cafc6b09-49db-407e-950e-bab9a6e60e9f_1p_js result, different session: c24314e8-1afc-4d9a-96a4-bc75e5d99b58_1p_js, aa3c8308-259e-464e-aa4f-6e3b827d137c_1p_js, 358e00ee-1af1-443e-8d23-1fa8923e03fc_1p_js, 7fe8a160-092e-4a52-81cd-841a2600cf16_1p_js, cafc6b09-49db-407e-950e-bab9a6e60e9f_1p_js unsupported: false, false, false, false, false passed: false, false, false, false, false test failed: false, false, false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same session: 91977509-fee5-471e-9ccb-9dd38fc58a67_1p_js, aab3ddfd-726f-4857-83c6-8d44ea5e6bb4_1p_js, 43c85c36-872d-485b-852e-5b322a7c7d45_1p_js result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same session: 48c217f0-1bef-4ff9-a86a-e02c452b3090_1p_js, 52225fb2-48b7-4a6d-8cba-f85356406aba_1p_js, 5616596f-2317-42fc-bd3f-f8e6bc122d3e_1p_js result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same session: a5be31f4-aa0a-4843-923b-3c4f83f5a928_1p_js, e31de4a2-0c0c-4125-b3cc-46d11e5579f9_1p_js, 8db17cd7-36fc-475c-8d65-e14f8da75dc6_1p_js result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
CookieStoreThe Cookie Store API is an alternative asynchronous API for managing cookies, supported by some browsers.
  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: 5465a603-de27-44f5-b8c4-707bfb613e2e_1p, 78421fc4-bf96-4cca-890a-80da7897dc6d_1p, 80b14108-7165-4df7-a9e6-ff02143416a6_1p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 716abdfe-395d-427a-95f5-86b590a83dbe_1p, 74b40c1c-a56c-422c-8ec2-977bc24c84e1_1p, a1abfa62-2197-4ef7-a6aa-1649c66a9829_1p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a_1p, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51_1p, 0e22765a-3b45-4d4f-96e1-155b36d72016_1p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
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 result, different session: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: true, true, true passed: undefined test failed: false, false, false
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 result, different session: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: true, true, true passed: undefined test failed: false, false, false
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 result, different session: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: true, true, true passed: undefined test failed: false, false, false
  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: c28bfb99-bfe7-484e-91ee-401936368f8e_1p, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6_1p, 41f02047-71ab-44db-a34c-341407f5d677_1p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
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
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 result, different session: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: true, true, true passed: undefined test failed: false, false, false
  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: 48c217f0-1bef-4ff9-a86a-e02c452b3090_1p, 52225fb2-48b7-4a6d-8cba-f85356406aba_1p, 5616596f-2317-42fc-bd3f-f8e6bc122d3e_1p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: a5be31f4-aa0a-4843-923b-3c4f83f5a928_1p, e31de4a2-0c0c-4125-b3cc-46d11e5579f9_1p, 8db17cd7-36fc-475c-8d65-e14f8da75dc6_1p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
CSS cacheCSS stylesheets are cached, and if that cache is shared between websites, it can be used to track users across sites.
  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_4564541146773713, fake_2692352112744054, fake_1884180604536274 result, different session: fake_8152245349293175, fake_3681928425910983, fake_7688466827010123 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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_8080095990695688, fake_8780721598644801, fake_45634861012866534 result, different session: fake_19808017119656296, fake_712157341298493, fake_5606699586588049 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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_506061582002066, fake_4123152501578917, fake_5158292020437387 result, different session: fake_23163586359817567, fake_8959227862457435, fake_8229950142018216 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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_4810163521447193, fake_8833953544184963, fake_6324331882169507 result, different session: fake_40502331983734385, fake_8038106050247189, fake_4964699263836334 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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_4509024400894093, fake_8619297145535438, fake_6900374563291392 result, different session: fake_6196406642563737, fake_5186833101497925, fake_18574941255531074 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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_33759679165418466, fake_5343761510667739, fake_4904233569738492 result, different session: fake_7592777685171157, fake_5175120019823607, fake_6028674523664195 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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_841237724704454, fake_6389539515788856, fake_546854836091961 result, different session: fake_7704163592051023, fake_9676892739056864, fake_18917184723247793 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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_42401296519219733, fake_05024707157742392, fake_5973490412393745, fake_4072946184290349, fake_12683279263368874 result, different session: fake_42401296519219733, fake_05024707157742392, fake_5973490412393745, fake_4072946184290349, fake_12683279263368874 unsupported: false, false, false, false, false passed: false, false, false, false, false test failed: false, false, false, false, false
  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_9226384292070655, fake_5226689439048489, fake_8892135794272285 result, different session: fake_04665166092978956, fake_6201552884994237, fake_7044883475905548 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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_0032635735577737357, fake_39956618542208155, fake_6607079971843715 result, different session: fake_39764207345279745, fake_5617581594391801, fake_9497691179961671 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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_39074804417896436, fake_6934253707979878, fake_8345598933080451 result, different session: fake_7839925798459115, fake_5109370024116018, fake_9112683674141697 unsupported: false, false, false passed: true, true, true test failed: false, false, false
favicon cacheA 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.
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 4, 4, 4 unsupported: false, false, false passed: true, true, true test failed: false, false, false
fetch cacheWhen a resource is received via the Fetch API, it is frequently cached. That cache can potentially be abused for cross-site tracking.
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
font cacheWeb fonts are sometimes stored in their own cache, which is vulnerable to being abused for cross-site tracking.
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
iframe cacheAn 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.
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
image cacheCaching of images in web browsers is a standard behavior. But if that cache leaks between websites, it can be abused for cross-site tracking.
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
indexedDBThe IndexedDB API exposes a transactional database to web pages. That database can be used to track users across websites, unless it is partitioned.
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: 5465a603-de27-44f5-b8c4-707bfb613e2e_1p, 78421fc4-bf96-4cca-890a-80da7897dc6d_1p, 80b14108-7165-4df7-a9e6-ff02143416a6_1p result, different session: undefined unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: 716abdfe-395d-427a-95f5-86b590a83dbe_1p, 74b40c1c-a56c-422c-8ec2-977bc24c84e1_1p, a1abfa62-2197-4ef7-a6aa-1649c66a9829_1p result, different session: undefined unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a_1p, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51_1p, 0e22765a-3b45-4d4f-96e1-155b36d72016_1p result, different session: undefined unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4_1p, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826_1p, cf35c52d-e97f-4820-82eb-d8054844f2c1_1p result, different session: undefined unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: e37747b4-8740-49ba-9270-601151aaf726_1p, e2e870e7-134c-4209-b335-78130b0eb740_1p, af1f42ee-1067-499d-8093-d4d19b5c49a6_1p result, different session: undefined unsupported: false, false, false passed: true, true, true test failed: false, false, false
write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: Error: A mutation operation was attempted on a database that did not allow mutations., Error: A mutation operation was attempted on a database that did not allow mutations., Error: A mutation operation was attempted on a database that did not allow mutations. result, different session: Error: A mutation operation was attempted on a database that did not allow mutations., Error: A mutation operation was attempted on a database that did not allow mutations., Error: A mutation operation was attempted on a database that did not allow mutations. unsupported: true, true, true passed: undefined test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: c28bfb99-bfe7-484e-91ee-401936368f8e_1p, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6_1p, 41f02047-71ab-44db-a34c-341407f5d677_1p result, different session: undefined unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: c24314e8-1afc-4d9a-96a4-bc75e5d99b58_1p, aa3c8308-259e-464e-aa4f-6e3b827d137c_1p, 358e00ee-1af1-443e-8d23-1fa8923e03fc_1p, 7fe8a160-092e-4a52-81cd-841a2600cf16_1p, cafc6b09-49db-407e-950e-bab9a6e60e9f_1p result, different session: c24314e8-1afc-4d9a-96a4-bc75e5d99b58_1p, aa3c8308-259e-464e-aa4f-6e3b827d137c_1p, 358e00ee-1af1-443e-8d23-1fa8923e03fc_1p, 7fe8a160-092e-4a52-81cd-841a2600cf16_1p, cafc6b09-49db-407e-950e-bab9a6e60e9f_1p unsupported: false, false, false, false, false passed: false, false, false, false, false test failed: false, false, false, false, false
write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: Error: A mutation operation was attempted on a database that did not allow mutations., Error: A mutation operation was attempted on a database that did not allow mutations., Error: A mutation operation was attempted on a database that did not allow mutations. result, different session: Error: A mutation operation was attempted on a database that did not allow mutations., Error: A mutation operation was attempted on a database that did not allow mutations., Error: A mutation operation was attempted on a database that did not allow mutations. unsupported: true, true, true passed: undefined test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: 48c217f0-1bef-4ff9-a86a-e02c452b3090_1p, 52225fb2-48b7-4a6d-8cba-f85356406aba_1p, 5616596f-2317-42fc-bd3f-f8e6bc122d3e_1p result, different session: undefined unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: a5be31f4-aa0a-4843-923b-3c4f83f5a928_1p, e31de4a2-0c0c-4125-b3cc-46d11e5579f9_1p, 8db17cd7-36fc-475c-8d65-e14f8da75dc6_1p result, different session: undefined unsupported: false, false, false passed: true, true, true test failed: false, false, false
localStorageThe 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.
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: 5465a603-de27-44f5-b8c4-707bfb613e2e_1p, 78421fc4-bf96-4cca-890a-80da7897dc6d_1p, 80b14108-7165-4df7-a9e6-ff02143416a6_1p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: 716abdfe-395d-427a-95f5-86b590a83dbe_1p, 74b40c1c-a56c-422c-8ec2-977bc24c84e1_1p, a1abfa62-2197-4ef7-a6aa-1649c66a9829_1p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a_1p, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51_1p, 0e22765a-3b45-4d4f-96e1-155b36d72016_1p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4_1p, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826_1p, cf35c52d-e97f-4820-82eb-d8054844f2c1_1p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: e37747b4-8740-49ba-9270-601151aaf726_1p, e2e870e7-134c-4209-b335-78130b0eb740_1p, af1f42ee-1067-499d-8093-d4d19b5c49a6_1p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: b71a2d50-2167-4614-a844-3de0e93814fb_1p, 87735b1f-b9af-4abe-8b23-8eb0096d3907_1p, e9f1e434-9ee8-4cdb-b17e-75370f35bfa9_1p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: c28bfb99-bfe7-484e-91ee-401936368f8e_1p, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6_1p, 41f02047-71ab-44db-a34c-341407f5d677_1p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: c24314e8-1afc-4d9a-96a4-bc75e5d99b58_1p, aa3c8308-259e-464e-aa4f-6e3b827d137c_1p, 358e00ee-1af1-443e-8d23-1fa8923e03fc_1p, 7fe8a160-092e-4a52-81cd-841a2600cf16_1p, cafc6b09-49db-407e-950e-bab9a6e60e9f_1p result, different session: c24314e8-1afc-4d9a-96a4-bc75e5d99b58_1p, aa3c8308-259e-464e-aa4f-6e3b827d137c_1p, 358e00ee-1af1-443e-8d23-1fa8923e03fc_1p, 7fe8a160-092e-4a52-81cd-841a2600cf16_1p, cafc6b09-49db-407e-950e-bab9a6e60e9f_1p unsupported: false, false, false, false, false passed: false, false, false, false, false test failed: false, false, false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: 91977509-fee5-471e-9ccb-9dd38fc58a67_1p, aab3ddfd-726f-4857-83c6-8d44ea5e6bb4_1p, 43c85c36-872d-485b-852e-5b322a7c7d45_1p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: 48c217f0-1bef-4ff9-a86a-e02c452b3090_1p, 52225fb2-48b7-4a6d-8cba-f85356406aba_1p, 5616596f-2317-42fc-bd3f-f8e6bc122d3e_1p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: a5be31f4-aa0a-4843-923b-3c4f83f5a928_1p, e31de4a2-0c0c-4125-b3cc-46d11e5579f9_1p, 8db17cd7-36fc-475c-8d65-e14f8da75dc6_1p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
prefetch cacheA 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.
  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: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
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 result, different session: Error: No requests received, Error: No requests received, Error: No requests received unsupported: true, true, true passed: undefined test failed: false, false, false
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 result, different session: Error: No requests received, Error: No requests received, Error: No requests received unsupported: true, true, true passed: undefined test failed: false, false, false
  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: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
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
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 result, different session: Error: No requests received, Error: No requests received, Error: No requests received unsupported: true, true, true passed: undefined test failed: false, false, false
  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: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
Web SQL DatabaseThe Web SQL Database is a deprecated web API for storing data in an SQL database.
  write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: 5465a603-de27-44f5-b8c4-707bfb613e2e_1p, 78421fc4-bf96-4cca-890a-80da7897dc6d_1p, 80b14108-7165-4df7-a9e6-ff02143416a6_1p result, different session: Error: could not prepare statement (1 no such table: cache), Error: could not prepare statement (1 no such table: cache), Error: could not prepare statement (1 no such table: cache) unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: 716abdfe-395d-427a-95f5-86b590a83dbe_1p, 74b40c1c-a56c-422c-8ec2-977bc24c84e1_1p, a1abfa62-2197-4ef7-a6aa-1649c66a9829_1p result, different session: Error: could not prepare statement (1 no such table: cache), Error: could not prepare statement (1 no such table: cache), Error: could not prepare statement (1 no such table: cache) unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a_1p, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51_1p, 0e22765a-3b45-4d4f-96e1-155b36d72016_1p result, different session: Error: could not prepare statement (1 no such table: cache), Error: could not prepare statement (1 no such table: cache), Error: could not prepare statement (1 no such table: cache) unsupported: false, false, false passed: true, true, true test failed: false, false, false
write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function result, different session: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function result, different session: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function result, different session: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function unsupported: true, true, true passed: undefined test failed: false, false, false
  write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: c28bfb99-bfe7-484e-91ee-401936368f8e_1p, 91c652e2-c96b-4855-ba1a-b3b4410bd9f6_1p, 41f02047-71ab-44db-a34c-341407f5d677_1p result, different session: Error: could not prepare statement (1 no such table: cache), Error: could not prepare statement (1 no such table: cache), Error: could not prepare statement (1 no such table: cache) unsupported: false, false, false passed: true, true, true test failed: false, false, false
write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: Error: Web SQL is deprecated, Error: Web SQL is deprecated, Error: Web SQL is deprecated, Error: Web SQL is deprecated, Error: Web SQL is deprecated result, different session: Error: Web SQL is deprecated, Error: Web SQL is deprecated, Error: Web SQL is deprecated, Error: Web SQL is deprecated, Error: Web SQL is deprecated unsupported: true, true, true, true, true passed: undefined test failed: false, false, false, false, false
write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function result, different session: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function unsupported: true, true, true passed: undefined test failed: false, false, false
  write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: 48c217f0-1bef-4ff9-a86a-e02c452b3090_1p, 52225fb2-48b7-4a6d-8cba-f85356406aba_1p, 5616596f-2317-42fc-bd3f-f8e6bc122d3e_1p result, different session: Error: could not prepare statement (1 no such table: cache), Error: could not prepare statement (1 no such table: cache), Error: could not prepare statement (1 no such table: cache) unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: a5be31f4-aa0a-4843-923b-3c4f83f5a928_1p, e31de4a2-0c0c-4125-b3cc-46d11e5579f9_1p, 8db17cd7-36fc-475c-8d65-e14f8da75dc6_1p result, different session: Error: could not prepare statement (1 no such table: cache), Error: could not prepare statement (1 no such table: cache), Error: could not prepare statement (1 no such table: cache) unsupported: false, false, false passed: true, true, true test failed: false, false, false
XMLHttpRequest cacheSimilar to the newer Fetch API, any resource received may be cached by the browser. The cache is potentially vulnerable to cross-site tracking attack.
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
Cross-session third-party tracking tests Which 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-SvcAlt-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.
  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, h3, h3 result, different session: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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, h3, h3 result, different session: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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, h3, h3 result, different session: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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, h3, h3 result, different session: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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, h3, h3 result, different session: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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, h3, h3 result, different session: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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, h3, h3 result, different session: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
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
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 result, different session: h2, h2, h2 unsupported: true, true, true passed: undefined test failed: false, false, false
  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, h3, h3 result, different session: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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, h3, h3 result, different session: h2, h2, h2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
CacheStorageThe 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.
write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${key}`]); } catch (e) { throw new Error("Unsupported"); } } read: async () => { let cache = await caches.open("supercookies"); let cacheKeys = await cache.keys(); let url = cacheKeys[0].url; return (new URL(url)).searchParams.get("key"); } result, same session: Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent. result, different session: Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${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: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent. result, different session: Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent. unsupported: true, true, true passed: undefined test failed: false, false, false
  write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${key}`]); } catch (e) { throw new Error("Unsupported"); } } read: async () => { let cache = await caches.open("supercookies"); let cacheKeys = await cache.keys(); let url = cacheKeys[0].url; return (new URL(url)).searchParams.get("key"); } result, same session: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a_3p, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51_3p, 0e22765a-3b45-4d4f-96e1-155b36d72016_3p result, different session: Error: Cannot read properties of undefined (reading 'url'), Error: Cannot read properties of undefined (reading 'url'), Error: Cannot read properties of undefined (reading 'url') unsupported: false, false, false passed: true, true, true test failed: false, false, false
write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${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: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. result, different session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${key}`]); } catch (e) { throw new Error("Unsupported"); } } read: async () => { let cache = await caches.open("supercookies"); let cacheKeys = await cache.keys(); let url = cacheKeys[0].url; return (new URL(url)).searchParams.get("key"); } result, same session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. result, different session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${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: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. result, different session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${key}`]); } catch (e) { throw new Error("Unsupported"); } } read: async () => { let cache = await caches.open("supercookies"); let cacheKeys = await cache.keys(); let url = cacheKeys[0].url; return (new URL(url)).searchParams.get("key"); } result, same session: Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent. result, different session: Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent. unsupported: true, true, true passed: undefined test failed: false, false, false
  write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${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: c24314e8-1afc-4d9a-96a4-bc75e5d99b58_3p, aa3c8308-259e-464e-aa4f-6e3b827d137c_3p, 358e00ee-1af1-443e-8d23-1fa8923e03fc_3p, 7fe8a160-092e-4a52-81cd-841a2600cf16_3p, cafc6b09-49db-407e-950e-bab9a6e60e9f_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
write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${key}`]); } catch (e) { throw new Error("Unsupported"); } } read: async () => { let cache = await caches.open("supercookies"); let cacheKeys = await cache.keys(); let url = cacheKeys[0].url; return (new URL(url)).searchParams.get("key"); } result, same session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. result, different session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${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: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent. result, different session: Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { try { let cache = await caches.open("supercookies"); cache.addAll([`test.css?key=${key}`]); } catch (e) { throw new Error("Unsupported"); } } read: async () => { let cache = await caches.open("supercookies"); let cacheKeys = await cache.keys(); let url = cacheKeys[0].url; return (new URL(url)).searchParams.get("key"); } result, same session: Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent. result, different session: Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent., Error: Failed to execute 'open' on 'CacheStorage': An attempt was made to break through the security policy of the user agent. unsupported: true, true, true passed: undefined test failed: false, false, false
cookie (HTTP)The cookie, first introduced by Netscape in 1994, is a small amount of data stored by your browser on a website's behalf. It has legitimate uses, but it is also the classic cross-site tracking mechanism, and today still the most popular method of tracking users across websites. Browsers can stop cookies from being used for cross-site tracking by either blocking or partitioning them.
  write: async (secret) => { // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value. await fetch(`${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: 5465a603-de27-44f5-b8c4-707bfb613e2e_3p_http, 78421fc4-bf96-4cca-890a-80da7897dc6d_3p_http, 80b14108-7165-4df7-a9e6-ff02143416a6_3p_http result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
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(`${baseURI}headers`); let cookie = (await response.json())["cookie"]; return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null; } result, same session: , , result, different session: , , unsupported: true, true, true passed: undefined test failed: false, false, false
  write: async (secret) => { // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value. await fetch(`${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: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a_3p_http, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51_3p_http, 0e22765a-3b45-4d4f-96e1-155b36d72016_3p_http result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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(`${baseURI}headers`); let cookie = (await response.json())["cookie"]; return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null; } result, same session: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4_3p_http, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826_3p_http, cf35c52d-e97f-4820-82eb-d8054844f2c1_3p_http result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value. await fetch(`${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: e37747b4-8740-49ba-9270-601151aaf726_3p_http, e2e870e7-134c-4209-b335-78130b0eb740_3p_http, af1f42ee-1067-499d-8093-d4d19b5c49a6_3p_http result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
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(`${baseURI}headers`); let cookie = (await response.json())["cookie"]; return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null; } result, same session: , , result, different session: , , unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (secret) => { // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value. await fetch(`${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 passed: undefined test failed: false, false, false
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(`${baseURI}headers`); let cookie = (await response.json())["cookie"]; return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null; } result, same session: , , , , result, different session: , , , , unsupported: true, true, true, true, true passed: undefined test failed: false, false, false, false, false
write: async (secret) => { // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value. await fetch(`${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 passed: undefined test failed: false, false, false
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(`${baseURI}headers`); let cookie = (await response.json())["cookie"]; return cookie ? cookie.match(/secret=([\w-]+)/)[1]: null; } result, same session: , , result, different session: , , unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (secret) => { // Request a page that will send an HTTPOnly 'set-cookie' response header with secret value. await fetch(`${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 passed: undefined test failed: false, false, 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.
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same session: 5465a603-de27-44f5-b8c4-707bfb613e2e_3p_js, 78421fc4-bf96-4cca-890a-80da7897dc6d_3p_js, 80b14108-7165-4df7-a9e6-ff02143416a6_3p_js result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
write: (secret) => { document.cookie = `secret=${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 passed: undefined test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same session: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a_3p_js, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51_3p_js, 0e22765a-3b45-4d4f-96e1-155b36d72016_3p_js result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same session: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4_3p_js, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826_3p_js, cf35c52d-e97f-4820-82eb-d8054844f2c1_3p_js result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same session: e37747b4-8740-49ba-9270-601151aaf726_3p_js, e2e870e7-134c-4209-b335-78130b0eb740_3p_js, af1f42ee-1067-499d-8093-d4d19b5c49a6_3p_js result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
write: (secret) => { document.cookie = `secret=${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 passed: undefined test failed: false, false, false
write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same session: , , result, different session: , , unsupported: true, true, true passed: undefined test failed: false, false, false
write: (secret) => { document.cookie = `secret=${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
write: (secret) => { document.cookie = `secret=${secret}_js; max-age=3600; SameSite=None; Secure`; } read: () => document.cookie ? document.cookie.match(/secret=([\w-]+)/)[1] : null result, same session: , , result, different session: , , unsupported: true, true, true passed: undefined test failed: false, false, false
write: (secret) => { document.cookie = `secret=${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 passed: undefined test failed: false, false, false
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 passed: undefined test failed: false, false, false
CookieStoreThe Cookie Store API is an alternative asynchronous API for managing cookies, supported by some browsers.
  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: 5465a603-de27-44f5-b8c4-707bfb613e2e_3p, 78421fc4-bf96-4cca-890a-80da7897dc6d_3p, 80b14108-7165-4df7-a9e6-ff02143416a6_3p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
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: , , result, different session: , , unsupported: true, true, true passed: undefined test failed: false, false, false
  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: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a_3p, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51_3p, 0e22765a-3b45-4d4f-96e1-155b36d72016_3p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
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 result, different session: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: true, true, true passed: undefined test failed: false, false, false
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 result, different session: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: true, true, true passed: undefined test failed: false, false, false
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 result, different session: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: true, true, true passed: undefined test failed: false, false, false
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: , , result, different session: , , unsupported: true, true, true passed: undefined test failed: false, false, false
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
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 result, different session: Error: Unsupported, Error: Unsupported, Error: Unsupported unsupported: true, true, true passed: undefined test failed: false, false, false
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: , , result, different session: , , unsupported: true, true, true passed: undefined test failed: false, false, false
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: , , result, different session: , , unsupported: true, true, true passed: undefined test failed: false, false, false
CSS cacheCSS stylesheets are cached, and if that cache is shared between websites, it can be used to track users across sites.
  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="${href}">`; const testElement = document.querySelector("#css"); let fontFamily; while (true) { await sleepMs(100); fontFamily = getComputedStyle(testElement).fontFamily; if (fontFamily.startsWith("fake")) { break; } } console.log(fontFamily); return fontFamily; } result, same session: fake_3567531501766865, fake_6909845287489003, fake_6727166314442328 result, different session: fake_4628685971363289, fake_7494807479935313, fake_9272318624581359 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { const href = testURI("resource", "css", key); const head = document.getElementsByTagName("head")[0]; head.innerHTML += `<link type="text/css" rel="stylesheet" href="${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="${href}">`; const testElement = document.querySelector("#css"); let fontFamily; while (true) { await sleepMs(100); fontFamily = getComputedStyle(testElement).fontFamily; if (fontFamily.startsWith("fake")) { break; } } console.log(fontFamily); return fontFamily; } result, same session: fake_943438149573733, fake_3003777954252964, fake_4077902671517928 result, different session: fake_14136609087660856, fake_1927334800590086, fake_5364679719374084 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { const href = testURI("resource", "css", key); const head = document.getElementsByTagName("head")[0]; head.innerHTML += `<link type="text/css" rel="stylesheet" href="${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="${href}">`; const testElement = document.querySelector("#css"); let fontFamily; while (true) { await sleepMs(100); fontFamily = getComputedStyle(testElement).fontFamily; if (fontFamily.startsWith("fake")) { break; } } console.log(fontFamily); return fontFamily; } result, same session: fake_9521035206226713, fake_3391727975315524, fake_20012090025769136 result, different session: fake_06099458514766165, fake_1566744813428289, fake_38971126116447263 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { const href = testURI("resource", "css", key); const head = document.getElementsByTagName("head")[0]; head.innerHTML += `<link type="text/css" rel="stylesheet" href="${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="${href}">`; const testElement = document.querySelector("#css"); let fontFamily; while (true) { await sleepMs(100); fontFamily = getComputedStyle(testElement).fontFamily; if (fontFamily.startsWith("fake")) { break; } } console.log(fontFamily); return fontFamily; } result, same session: fake_877099713882276, fake_7449103467858427, fake_22629859311608436 result, different session: fake_5952109873258757, fake_9487886564820429, fake_16365608795846165 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { const href = testURI("resource", "css", key); const head = document.getElementsByTagName("head")[0]; head.innerHTML += `<link type="text/css" rel="stylesheet" href="${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="${href}">`; const testElement = document.querySelector("#css"); let fontFamily; while (true) { await sleepMs(100); fontFamily = getComputedStyle(testElement).fontFamily; if (fontFamily.startsWith("fake")) { break; } } console.log(fontFamily); return fontFamily; } result, same session: fake_2168851372750149, fake_9023432622959551, fake_2614429809083567 result, different session: fake_12176805336784602, fake_352817493365049, fake_6832539753879558 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { const href = testURI("resource", "css", key); const head = document.getElementsByTagName("head")[0]; head.innerHTML += `<link type="text/css" rel="stylesheet" href="${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="${href}">`; const testElement = document.querySelector("#css"); let fontFamily; while (true) { await sleepMs(100); fontFamily = getComputedStyle(testElement).fontFamily; if (fontFamily.startsWith("fake")) { break; } } console.log(fontFamily); return fontFamily; } result, same session: fake_035569870275036, fake_27298594451332603, fake_25280994554167724 result, different session: fake_901458722774652, fake_6220889041756581, fake_4450643027393164 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { const href = testURI("resource", "css", key); const head = document.getElementsByTagName("head")[0]; head.innerHTML += `<link type="text/css" rel="stylesheet" href="${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="${href}">`; const testElement = document.querySelector("#css"); let fontFamily; while (true) { await sleepMs(100); fontFamily = getComputedStyle(testElement).fontFamily; if (fontFamily.startsWith("fake")) { break; } } console.log(fontFamily); return fontFamily; } result, same session: fake_9364899585901822, fake_04914166493105809, fake_2289667817293346 result, different session: fake_974381040884428, fake_07156533808899068, fake_008668668603951657 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { const href = testURI("resource", "css", key); const head = document.getElementsByTagName("head")[0]; head.innerHTML += `<link type="text/css" rel="stylesheet" href="${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="${href}">`; const testElement = document.querySelector("#css"); let fontFamily; while (true) { await sleepMs(100); fontFamily = getComputedStyle(testElement).fontFamily; if (fontFamily.startsWith("fake")) { break; } } console.log(fontFamily); return fontFamily; } result, same session: fake_8636922815505284, fake_8501286352538855, fake_5726516249236855, fake_15988310280682372, fake_3171513889502664 result, different session: fake_8636922815505284, fake_8501286352538855, fake_5726516249236855, fake_15988310280682372, fake_3171513889502664 unsupported: false, false, false, false, false passed: false, false, false, false, false test failed: false, false, false, false, false
  write: async (key) => { const href = testURI("resource", "css", key); const head = document.getElementsByTagName("head")[0]; head.innerHTML += `<link type="text/css" rel="stylesheet" href="${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="${href}">`; const testElement = document.querySelector("#css"); let fontFamily; while (true) { await sleepMs(100); fontFamily = getComputedStyle(testElement).fontFamily; if (fontFamily.startsWith("fake")) { break; } } console.log(fontFamily); return fontFamily; } result, same session: fake_7335239224553736, fake_46211144501712087, fake_6791323702797807 result, different session: fake_2246349634584457, fake_9948099834034083, fake_09605476579151939 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { const href = testURI("resource", "css", key); const head = document.getElementsByTagName("head")[0]; head.innerHTML += `<link type="text/css" rel="stylesheet" href="${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="${href}">`; const testElement = document.querySelector("#css"); let fontFamily; while (true) { await sleepMs(100); fontFamily = getComputedStyle(testElement).fontFamily; if (fontFamily.startsWith("fake")) { break; } } console.log(fontFamily); return fontFamily; } result, same session: fake_6330296825219632, fake_8574247443551326, fake_7550636413106298 result, different session: fake_5294906233448886, fake_11078101779038763, fake_9154522190027061 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { const href = testURI("resource", "css", key); const head = document.getElementsByTagName("head")[0]; head.innerHTML += `<link type="text/css" rel="stylesheet" href="${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_5014702688649622, fake_9952899709726801, fake_9425779560577281 result, different session: fake_4053592476326231, fake_843555611310923, fake_8865052524878971 unsupported: false, false, false passed: true, true, true test failed: false, false, false
favicon cacheA 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.
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 4, 4, 4 unsupported: false, false, false passed: true, true, true test failed: false, false, false
fetch cacheWhen a resource is received via the Fetch API, it is frequently cached. That cache can potentially be abused for cross-site tracking.
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
font cacheWeb fonts are sometimes stored in their own cache, which is vulnerable to being abused for cross-site tracking.
  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("${fontURI}"); } #text { font-family: "myFont" }`; document.getElementsByTagName("head")[0].appendChild(style); let newWidth; do { await sleepMs(100); newWidth = text.getBoundingClientRect().width; } while (newWidth < 0 || newWidth === originalWidth) let response = await fetch( testURI("ctr", "font", key), {"cache": "reload"}); return (await response.text()).trim(); } result, same session: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { let style = document.createElement("style"); style.type='text/css'; let fontURI = testURI("resource", "font", key); style.innerHTML = `@font-face {font-family: "myFont"; src: url("${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("${fontURI}"); } #text { font-family: "myFont" }`; document.getElementsByTagName("head")[0].appendChild(style); let newWidth; do { await sleepMs(100); newWidth = text.getBoundingClientRect().width; } while (newWidth < 0 || newWidth === originalWidth) let response = await fetch( testURI("ctr", "font", key), {"cache": "reload"}); return (await response.text()).trim(); } result, same session: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { let style = document.createElement("style"); style.type='text/css'; let fontURI = testURI("resource", "font", key); style.innerHTML = `@font-face {font-family: "myFont"; src: url("${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("${fontURI}"); } #text { font-family: "myFont" }`; document.getElementsByTagName("head")[0].appendChild(style); let newWidth; do { await sleepMs(100); newWidth = text.getBoundingClientRect().width; } while (newWidth < 0 || newWidth === originalWidth) let response = await fetch( testURI("ctr", "font", key), {"cache": "reload"}); return (await response.text()).trim(); } result, same session: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { let style = document.createElement("style"); style.type='text/css'; let fontURI = testURI("resource", "font", key); style.innerHTML = `@font-face {font-family: "myFont"; src: url("${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("${fontURI}"); } #text { font-family: "myFont" }`; document.getElementsByTagName("head")[0].appendChild(style); let newWidth; do { await sleepMs(100); newWidth = text.getBoundingClientRect().width; } while (newWidth < 0 || newWidth === originalWidth) let response = await fetch( testURI("ctr", "font", key), {"cache": "reload"}); return (await response.text()).trim(); } result, same session: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { let style = document.createElement("style"); style.type='text/css'; let fontURI = testURI("resource", "font", key); style.innerHTML = `@font-face {font-family: "myFont"; src: url("${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("${fontURI}"); } #text { font-family: "myFont" }`; document.getElementsByTagName("head")[0].appendChild(style); let newWidth; do { await sleepMs(100); newWidth = text.getBoundingClientRect().width; } while (newWidth < 0 || newWidth === originalWidth) let response = await fetch( testURI("ctr", "font", key), {"cache": "reload"}); return (await response.text()).trim(); } result, same session: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { let style = document.createElement("style"); style.type='text/css'; let fontURI = testURI("resource", "font", key); style.innerHTML = `@font-face {font-family: "myFont"; src: url("${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("${fontURI}"); } #text { font-family: "myFont" }`; document.getElementsByTagName("head")[0].appendChild(style); let newWidth; do { await sleepMs(100); newWidth = text.getBoundingClientRect().width; } while (newWidth < 0 || newWidth === originalWidth) let response = await fetch( testURI("ctr", "font", key), {"cache": "reload"}); return (await response.text()).trim(); } result, same session: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { let style = document.createElement("style"); style.type='text/css'; let fontURI = testURI("resource", "font", key); style.innerHTML = `@font-face {font-family: "myFont"; src: url("${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("${fontURI}"); } #text { font-family: "myFont" }`; document.getElementsByTagName("head")[0].appendChild(style); let newWidth; do { await sleepMs(100); newWidth = text.getBoundingClientRect().width; } while (newWidth < 0 || newWidth === originalWidth) let response = await fetch( testURI("ctr", "font", key), {"cache": "reload"}); return (await response.text()).trim(); } result, same session: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { let style = document.createElement("style"); style.type='text/css'; let fontURI = testURI("resource", "font", key); style.innerHTML = `@font-face {font-family: "myFont"; src: url("${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("${fontURI}"); } #text { font-family: "myFont" }`; document.getElementsByTagName("head")[0].appendChild(style); let newWidth; do { await sleepMs(100); newWidth = text.getBoundingClientRect().width; } while (newWidth < 0 || newWidth === originalWidth) let response = await fetch( testURI("ctr", "font", key), {"cache": "reload"}); return (await response.text()).trim(); } result, same session: 1, 1, 1, 1, 1 result, different session: 1, 1, 1, 1, 1 unsupported: false, false, false, false, false passed: false, false, false, false, false test failed: false, false, false, false, false
  write: async (key) => { let style = document.createElement("style"); style.type='text/css'; let fontURI = testURI("resource", "font", key); style.innerHTML = `@font-face {font-family: "myFont"; src: url("${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("${fontURI}"); } #text { font-family: "myFont" }`; document.getElementsByTagName("head")[0].appendChild(style); let newWidth; do { await sleepMs(100); newWidth = text.getBoundingClientRect().width; } while (newWidth < 0 || newWidth === originalWidth) let response = await fetch( testURI("ctr", "font", key), {"cache": "reload"}); return (await response.text()).trim(); } result, same session: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { let style = document.createElement("style"); style.type='text/css'; let fontURI = testURI("resource", "font", key); style.innerHTML = `@font-face {font-family: "myFont"; src: url("${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("${fontURI}"); } #text { font-family: "myFont" }`; document.getElementsByTagName("head")[0].appendChild(style); let newWidth; do { await sleepMs(100); newWidth = text.getBoundingClientRect().width; } while (newWidth < 0 || newWidth === originalWidth) let response = await fetch( testURI("ctr", "font", key), {"cache": "reload"}); return (await response.text()).trim(); } result, same session: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (key) => { let style = document.createElement("style"); style.type='text/css'; let fontURI = testURI("resource", "font", key); style.innerHTML = `@font-face {font-family: "myFont"; src: url("${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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
iframe cacheAn 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.
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
image cacheCaching of images in web browsers is a standard behavior. But if that cache leaks between websites, it can be abused for cross-site tracking.
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
indexedDBThe IndexedDB API exposes a transactional database to web pages. That database can be used to track users across websites, unless it is partitioned.
write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: Error: The user denied permission to access the database., Error: The user denied permission to access the database., Error: The user denied permission to access the database. result, different session: Error: The user denied permission to access the database., Error: The user denied permission to access the database., Error: The user denied permission to access the database. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: Error: The user denied permission to access the database., Error: The user denied permission to access the database., Error: The user denied permission to access the database. result, different session: Error: The user denied permission to access the database., Error: The user denied permission to access the database., Error: The user denied permission to access the database. unsupported: true, true, true passed: undefined test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a_3p, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51_3p, 0e22765a-3b45-4d4f-96e1-155b36d72016_3p result, different session: undefined unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4_3p, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826_3p, cf35c52d-e97f-4820-82eb-d8054844f2c1_3p result, different session: undefined unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: e37747b4-8740-49ba-9270-601151aaf726_3p, e2e870e7-134c-4209-b335-78130b0eb740_3p, af1f42ee-1067-499d-8093-d4d19b5c49a6_3p result, different session: undefined unsupported: false, false, false passed: true, true, true test failed: false, false, false
write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. result, different session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: Error: The user denied permission to access the database., Error: The user denied permission to access the database., Error: The user denied permission to access the database. result, different session: Error: The user denied permission to access the database., Error: The user denied permission to access the database., Error: The user denied permission to access the database. unsupported: true, true, true passed: undefined test failed: false, false, false
  write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: c24314e8-1afc-4d9a-96a4-bc75e5d99b58_3p, aa3c8308-259e-464e-aa4f-6e3b827d137c_3p, 358e00ee-1af1-443e-8d23-1fa8923e03fc_3p, 7fe8a160-092e-4a52-81cd-841a2600cf16_3p, cafc6b09-49db-407e-950e-bab9a6e60e9f_3p result, different session: undefined unsupported: false, false, false, false, false passed: true, true, true, true, true test failed: false, false, false, false, false
write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. result, different session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: Error: The user denied permission to access the database., Error: The user denied permission to access the database., Error: The user denied permission to access the database. result, different session: Error: The user denied permission to access the database., Error: The user denied permission to access the database., Error: The user denied permission to access the database. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (secret) => { try { return await IdbKeyVal.set("secret", secret); } catch (e) { throw new Error("Unsupported"); } } read: () => IdbKeyVal.get("secret") result, same session: Error: The user denied permission to access the database., Error: The user denied permission to access the database., Error: The user denied permission to access the database. result, different session: Error: The user denied permission to access the database., Error: The user denied permission to access the database., Error: The user denied permission to access the database. unsupported: true, true, true passed: undefined test failed: false, false, false
localStorageThe 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.
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: 5465a603-de27-44f5-b8c4-707bfb613e2e_3p, 78421fc4-bf96-4cca-890a-80da7897dc6d_3p, 80b14108-7165-4df7-a9e6-ff02143416a6_3p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document. result, different session: Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document. unsupported: true, true, true passed: undefined test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: 499d70a2-e9f7-41f7-998e-f5bc1ea9d72a_3p, 649e5b9f-17af-47a2-9bb7-d04dfd4c3b51_3p, 0e22765a-3b45-4d4f-96e1-155b36d72016_3p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: 28bf649b-c9d9-4c41-bbb1-ca4c9e0264a4_3p, 3b1a07e6-6d4a-4740-8bfa-f2901dcd7826_3p, cf35c52d-e97f-4820-82eb-d8054844f2c1_3p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: e37747b4-8740-49ba-9270-601151aaf726_3p, e2e870e7-134c-4209-b335-78130b0eb740_3p, af1f42ee-1067-499d-8093-d4d19b5c49a6_3p result, different session: , , unsupported: false, false, false passed: true, true, true test failed: false, false, false
write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. result, different session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: true, true, true passed: undefined test failed: false, false, false
write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document. result, different session: Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document. unsupported: true, true, true passed: undefined test failed: false, false, false
  write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: c24314e8-1afc-4d9a-96a4-bc75e5d99b58_3p, aa3c8308-259e-464e-aa4f-6e3b827d137c_3p, 358e00ee-1af1-443e-8d23-1fa8923e03fc_3p, 7fe8a160-092e-4a52-81cd-841a2600cf16_3p, cafc6b09-49db-407e-950e-bab9a6e60e9f_3p result, different session: , , , , unsupported: false, false, false, false, false passed: true, true, true, true, true test failed: false, false, false, false, false
write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. result, different session: Error: The operation is insecure., Error: The operation is insecure., Error: The operation is insecure. unsupported: true, true, true passed: undefined test failed: false, false, false
write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document. result, different session: Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document. unsupported: true, true, true passed: undefined test failed: false, false, false
write: (secret) => localStorage.setItem("secret", secret) read: () => localStorage.getItem("secret") result, same session: Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document. result, different session: Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document., Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document. unsupported: true, true, true passed: undefined test failed: false, false, false
prefetch cacheA 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.
  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: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different session: 1, 1, 1 unsupported: false, false, false passed: false, false, false test failed: false, false, false
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 result, different session: Error: No requests received, Error: No requests received, Error: No requests received unsupported: true, true, true passed: undefined test failed: false, false, false
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 result, different session: Error: No requests received, Error: No requests received, Error: No requests received unsupported: true, true, true passed: undefined test failed: false, false, false
  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: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
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
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 result, different session: Error: No requests received, Error: No requests received, Error: No requests received unsupported: true, true, true passed: undefined test failed: false, false, false
  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: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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: 1, 1, 1 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
Web SQL DatabaseThe Web SQL Database is a deprecated web API for storing data in an SQL database.
write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts. result, different session: Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts. result, different session: Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts. result, different session: Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function result, different session: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function result, different session: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function result, different session: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts. result, different session: Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: Error: Web SQL is deprecated, Error: Web SQL is deprecated, Error: Web SQL is deprecated, Error: Web SQL is deprecated, Error: Web SQL is deprecated result, different session: Error: Web SQL is deprecated, Error: Web SQL is deprecated, Error: Web SQL is deprecated, Error: Web SQL is deprecated, Error: Web SQL is deprecated unsupported: true, true, true, true, true passed: undefined test failed: false, false, false, false, false
write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function result, different session: Error: window.openDatabase is not a function, Error: window.openDatabase is not a function, Error: window.openDatabase is not a function unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts. result, different session: Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts. unsupported: true, true, true passed: undefined test failed: false, false, false
write: async (key) => { if (!window.openDatabase) { throw new Error("gported"); } let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let tx = new Promise((resolve) => database.transaction(tx => { tx.executeSql( `CREATE TABLE IF NOT EXISTS cache( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, value TEXT NOT NULL, UNIQUE (name) )`, [], (tx, rs) => {}, (tx, err) => {}); tx.executeSql( `INSERT OR REPLACE INTO cache(name, value) VALUES(?, ?)`, ["secret", key], (tx, rs) => {}, (tx, rs) => {}); })); } read: async () => { let database = window.openDatabase("sqlite_supercookie", "", "supercookie", 1024 * 1024); let result = await new Promise((resolve, reject) => database.transaction(tx => { tx.executeSql( "SELECT value FROM cache WHERE name=?", ["secret"], (tx, rs) => resolve(rs), (tx, err) => reject(err)); })); return result.rows.item(0).value; } result, same session: Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts. result, different session: Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts., Error: Failed to execute 'openDatabase' on 'Window': Access to the WebDatabase API is denied in third party contexts. unsupported: true, true, true passed: undefined test failed: false, false, false
XMLHttpRequest cacheSimilar to the newer Fetch API, any resource received may be cached by the browser. The cache is potentially vulnerable to cross-site tracking attack.
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false
  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 result, different session: 2, 2, 2 unsupported: false, false, false passed: true, true, true test failed: false, false, false