Exposes to PerformanceObserver the initial visibility state of a page plus any visibility state changes that the page goes through. Also adds support for this to the observe() method's buffered flag.


Currently the Page Visibility API enables querying the current visibility state of the page and adding an event handler which will be executed when the visibility state changes in the future. However, this creates a gap for developers that are interested in knowing the full visibility states of the page, from the beginning of the page load: the initial visibility state and any very early visibility state changes that occur before JavaScript has had a chance to query the visibility state or register an event handler.



Specification link

Unknown standards status - check spec link for status

Status in Chromium


Proposed (tracking bug)

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.

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Last updated on 2021-12-11