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This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

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 Working Draft  

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 47 No support 53 (53)[1] No support 34 No support
Feature Android Chrome Firefox Mobile (Gecko) Firefox OS IE Phone Opera Mobile Safari Mobile
Basic support 53 55 53.0 (53)[1] ? No support 37 No support

[1] Idle callback support was added in Firefox 53, but was disabled by default. To enable it, set the preference dom.requestIdleCallback.enabled to true. Idle callbacks are enabled by default starting in Firefox 55.

See also


Document Tags and Contributors

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