As an intervention we want to limit the rate at which timers in out-of-view, cross-origin frames are able to fire. Until very recently it wasn't possible for script authors to easily determine whether their content was visible to the user or not. A common pattern therefore is to use a continuous setTimeout() loop for driving animations without considering visibility, which can be very costly for performance.



Status in Chromium


Browser Intervention (tracking bug)

Consensus & Standardization

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



A potential compatibility risk is that a site can observe timers firing out-of-order if the timers are scheduled from a mix of visible and hidden frames. To reduce this risk, we propose to only throttle timers in cross-origin frames.

Last updated on 2021-01-02