Animation.playbackRate

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

The Animation.playbackRate property of the Web Animations API returns or sets the playback rate of the animation.

Animations have a playback rate that provides a scaling factor from the rate of change of the animation's timeline time values to the animation’s current time. The playback rate is initially 1.

Syntax

var currentPlaybackRate = Animation.playbackRate;

Animation.playbackRate = newRate;

Value

Takes a number that can be 0, negative, or positive. Negative values reverse the animation. The value is a scaling factor, so for example a value of 2 would double the playback rate.

Setting an animation’s playbackRate to 0 effectively pauses the animation (however, its playstate does not necessarily become paused).

Examples

In the Growing/Shrinking Alice Game example, clicking or tapping the bottle causes Alice's growing animation (aliceChange) to reverse, causing her to shrink:

var shrinkAlice = function() {
  aliceChange.playbackRate = -1;
  aliceChange.play();
}

// On tap or click, Alice will shrink.
bottle.addEventListener("mousedown", shrinkAlice, false);
bottle.addEventListener("touchstart", shrinkAlice, false);

Contrariwise, clicking on the cake causes her to "grow," playing aliceChange forwards again:

var growAlice = function() {
  aliceChange.playbackRate = 1;
  aliceChange.play();  
}

// On tap or click, Alice will grow.
cake.addEventListener("mousedown", growAlice, false);
cake.addEventListener("touchstart", growAlice, false);

In another example, the Red Queen's Race Game, Alice and the Red Queen are constantly slowing down:

setInterval( function() {

  // Make sure the playback rate never falls below .4

  if (redQueen_alice.playbackRate > .4) {
    redQueen_alice.playbackRate *= .9;    
  }

}, 3000);

But clicking or tapping on them causes them to speed up by multiplying their playbackRate:

var goFaster = function() {
  redQueen_alice.playbackRate *= 1.1;
}

document.addEventListener("click", goFaster);
document.addEventListener("touchstart", goFaster);

Specifications

Specification Status Comment
Web Animations
The definition of 'Animation.playbackRate' in that specification.
Working Draft  

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Basic support
Experimental
Chrome Full support 39Edge ? Firefox Full support 48
Full support 48
No support 42 — 48
Disabled
Disabled From version 42 until version 48 (exclusive): this feature is behind the dom.animations-api.core.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE No support NoOpera Full support 26Safari No support NoWebView Android Full support 39Chrome Android Full support 39Edge Mobile ? Firefox Android Full support 48
Full support 48
No support 42 — 48
Disabled
Disabled From version 42 until version 48 (exclusive): this feature is behind the dom.animations-api.core.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 26Safari iOS No support NoSamsung Internet Android Full support 4.0

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
User must explicitly enable this feature.
User must explicitly enable this feature.

See also

Document Tags and Contributors

Last updated by: fscholz,