Animation.updatePlaybackRate()

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

The updatePlaybackRate() method of the Web Animations API's Animation Interface sets the speed of an animation after first synchronizing its playback position.

In some cases, an animation may run on a separate thread or process and will continue updating even while long-running JavaScript delays the main thread. In such a case, setting the playbackRate on the animation directly may cause the animation's playback position to jump since its playback position on the main thread may have drifted from the playback position where it is currently running.

updatePlaybackRate() is an asynchronous method that sets the speed of an animation after synchronizing with its current playback position, ensuring that the resulting change in speed does not produce a sharp jump. After calling updatePlaybackRate() the animation's playbackRate is not immediately updated. It will be updated once the animation's ready promise is resolved.

Syntax

Animation.updatePlaybackRate(2);

Parameters

playbackRate: The new speed to set. This may be a positive number (to speed up or slow down the animation), a negative number (to make it play backwards), or zero (to effectively pause the animation).

Return value

None.

Examples

A speed selector component would benefit from smooth updating of updatePlaybackRate(), as demonstrated below:

speedSelector.addEventListener('input', evt => {
  cartoon.updatePlaybackRate(parseFloat(evt.target.value));
  cartoon.ready.then(() => {
    console.log(`Playback rate set to ${cartoon.playbackRate}`);
  });
});

Specifications

Specification	Status	Comment
Web Animations The definition of 'updatePlaybackRate()' in that specification.	Working Draft

Browser compatibility

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`updatePlaybackRate` Experimental	Chrome No support No	Edge No support No	Firefox Full support 60	IE No support No	Opera No support No	Safari No support No	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 60	Opera Android No support No	Safari iOS No support No	Samsung Internet Android No support No

Legend

Full support: Full support
No support: No support
Experimental. Expect behavior to change in the future.: Experimental. Expect behavior to change in the future.