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

The KeyframeEffect interface of the Web Animations API lets us create sets of animatable properties and values, called keyframes. These can then be played using the Animation() constructor.


Returns a new KeyframeEffect object instance, and also allows you to clone an existing keyframe effect object instance.


This interface inherits some of its methods and properties from its parent, KeyframeEffectReadOnly, and its grandparent AnimationEffectReadOnly.

The AnimationEffectTimingReadOnly object associated with the animation containing all the animation's timing values.
Gets and sets the element or pseudo-element being animated by this object. This may be null for animations that do not target a specific element.

Future properties

The following options are currently not shipped anywhere, but will be added in the near future.

Gets and sets the iteration composite operation for resolving the property value changes of this keyframe effect.
Gets and sets the composite operation property for resolving the property value changes between this and other keyframe effects.


Returns the computed keyframes that make up this effect along with their computed keyframe offsets.
Replaces the set of keyframes that make up this effect.
Returns the calculated, current timing values for this keyframe effect.


In the Follow the White Rabbit example, the KeyframeEffect constructor is used to create a set of keyframes that dictate how the White Rabbit should animate down the hole:

 var rabbitDownKeyframes = new KeyframeEffect( 
    whiteRabbit, // element to animate
      { transform: 'translateY(0%)' }, // keyframe 
      { transform: 'translateY(100%)' } // keyframe
    { duration: 3000, fill: 'forwards' } // keyframe options


Specification Status Comment
Web Animations
The definition of 'KeyframeEffect' in that specification.
Working Draft Initial definition

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes ?481 No No No
Clone constructor (2nd type of constructor) Yes ? No2 No No No
setKeyframes No No No No No No
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes ?481 No No ?
Clone constructor (2nd type of constructor) Yes Yes ? No2 No No ?
setKeyframes No No No No No No ?

1. The Web Animations API is only enabled by default in Firefox Nightly builds. It was enabled in Developer Edition until 58, when it is no longer enabled by default. 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.

2. Only enabled in Firefox 52 and later Nightly edition. Turned off in Beta/release.

See also

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 Last updated by: fscholz,