demo · v136

Visited Partitioning

Click a link to mark it visited from this origin, then look at the "partition key" that Chrome 136 stores. Same URL viewed from a different (top-level, frame) origin will not paint as visited.

rose & bold = your browser styled it as :visited from this origin.

same-site links (this origin)

cross-site links

partition key for THIS page

The same link URL is now keyed against this combination. A frame on another origin embedding the same URL would have a different key and would not paint as :visited.

link URL/v136/
top-level site
frame origin

cross-site iframe — should NOT paint as visited

Below, we embed this page's own URL inside an iframe served from data: (different origin). Click /v136/ above first, then look at the iframe — its /v136/ link is unvisited because the (top, frame) origin pair differs.

the code

// Pre-136: VisitedLinks hashtable keyed on URL alone
//   key = hash(url)
// 136+: triple-keyed
//   key = hash(url, top-level-site, frame-origin)
//
// So `a[href="https://example.com/"]:visited` only paints rose
// if THIS top-level site & frame origin clicked it before.

see also