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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 read-only Animation.ready property of the Web Animations API returns a Promise which resolves when the animation is ready to play. A new promise is created every time the animation enters the "pending" play state as well as when the animation is canceled, since in both of those scenarios, the animation is ready to be started again.

Since the same Promise is used for both pending play and pending pause requests, authors are advised to check the state of the animation when the promise is resolved.


var readyPromise = Animation.ready;


A Promise which resolves when the animation is ready to be played. You'll typically use a construct similar to this when using the ready promise:

animation.ready.then(function() {
  // Do whatever needs to be done when
  // the animation is ready to run


In the following example, the state of the animation will be running when the current ready Promise is resolved because the animation does not leave the pending play state in between the calls to pause and play and hence the current ready Promise does not change.

animation.ready.then(function() {
  // Displays 'running'


Specification Status Comment
Web Animations
The definition of 'Animation.ready' in that specification.
Working Draft Editor's draft.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support No support 48 (48)[1] No support No support No support
Feature Android Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support No support 48.0 (48)[1] No support No support No support

[1] The Web Animations API is only enabled by default in Firefox Developer Edition and Nightly builds. You can enable it in beta and release builds by setting the preference dom.animations-api.core.enabled to true, and can disable it in any Firefox version by setting this preference to false.

See also

Document Tags and Contributors

 Contributors to this page: Sheppy, birtles, chrisdavidmills, rachelnabors
 Last updated by: Sheppy,