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conformance · v139

v139 · faster-background-freezing-on-android — conformance probe

6 assertions drawn from the spec. Each is a single contract the spec text makes. Pass/fail reflects what this browser executed; blocked means the contract was not run because it needs user mediation, hardware, or another unavailable precondition. Open the page in Chrome stable / canary / Firefox / Safari to compare.

browser: spec: https://html.spec.whatwg.org/multipage/interaction.html#page-visibility chromestatus: #5386725031149568 generated 2026-06-01T08:13:31Z by conformance-author-v1-subagent
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id contract kind verdict detail
document-visibility-state document.visibilityState is the spec-defined signal that flips before a page is frozen — Chrome 139 uses this same lifecycle just with a tighter Android timer. typeof
document-hidden-flag document.hidden is exposed as the boolean shortcut for visibilityState !== 'visible'. typeof
visibilitychange-event-supported document.addEventListener('visibilitychange', ...) is accepted; this is the event that fires before background freezing. script
freeze-and-resume-events-on-document Page Lifecycle 'freeze'/'resume' events are observable on document — these are the events delivered when Android backgrounds the tab and freezes it (faster in v139). spec ↗ script
page-transition-event-supported PageTransitionEvent is exposed (used for pageshow/pagehide which fire around freeze/resume). exists
useragent-android-marker-when-applicable If the visitor is on Android, the UA contains 'Android' (the platform the faster freezing actually applies to). script