This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The timeRemaining() method on the IdleDeadline interface returns the estimated number of milliseconds remaining in the current idle period. The callback can call this method at any time to determine how much time it can continue to work before it must return. For example, if the callback finishes a task and has another one to begin, it can call timeRemaining() to see if there's enough time to complete the next task. If there isn't, the callback can just return immediately, or look for other work to do with the remaining time.

By the time timeRemaining() reaches 0, the callback must return control to the user agent's event loop.


timeRemaining = IdleDeadline.timeRemaining();

Return value

A DOMHighResTimeStamp value (which is a floating-point number) representing the number of milliseconds the user agent estimates are left in the current idle period. The value is ideally accurate to within about 5 microseconds.

If the IdleDeadline object's didTimeout property is true, this method returns zero.


See our complete example in the article Cooperative Scheduling of Background Tasks API.


Specification Status Comment
Cooperative Scheduling of Background Tasks Proposed Recommendation  

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support47 No



No34 No
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support4747 No



37 No ?

1. From version 53: this feature is behind the dom.requestIdleCallback.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

See also


Document Tags and Contributors

Contributors to this page: fscholz, Sheppy
Last updated by: fscholz,