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 KeyframeEffect()
constructor of the Web Animations API returns a new
object instance, and also allows you to clone an existing keyframe effect object instance.KeyframeEffect
Syntax
var keyframes = new KeyframeEffect(element, keyframeSet, keyframeOptions); var keyframes = new KeyframeEffect(sourceKeyFrames);
Parameters
The first type of constructor (see above) creates a completely new KeyframeEffectReadOnly
object instance. Its parameters are:
- element
- The DOM element to be animated, or
null
. - keyframeSet
- An keyframe object or
null
. - keyframeOptions Optional
-
Either an integer representing the animation's duration (in milliseconds), or an
Object
containing one or more of the following:
delay
Optional- The number of milliseconds to delay the start of the animation. Defaults to 0.
direction
Optional- Whether the animation runs forwards (
normal
), backwards (reverse
), switches direction after each iteration (alternate
), or runs backwards and switches direction after each iteration (alternate-reverse
). Defaults to"normal"
. duration
Optional- The number of milliseconds each iteration of the animation takes to complete. Defaults to 0. Although this is technically optional, keep in mind that your animation will not run if this value is 0.
easing
Optional- The rate of the animation's change over time. Accepts the pre-defined values
"linear"
,"ease"
,"ease-in"
,"ease-out"
, and"ease-in-out"
, or a custom"cubic-bezier"
value like"cubic-bezier(0.42, 0, 0.58, 1)"
. Defaults to"linear"
. endDelay
Optional- The number of milliseconds to delay after the end of an animation. This is primarily of use when sequencing animations based on the end time of another animation. Defaults to 0.
fill
Optional- Dictates whether the animation's effects should be reflected by the element(s) prior to playing (
"backwards"
), retained after the animation has completed playing ("forwards"
), orboth
. Defaults to"none"
. iterationStart
Optional- Describes at what point in the iteration the animation should start. 0.5 would indicate starting halfway through the first iteration for example, and with this value set, an animation with 2 iterations would end halfway through a third iteration. Defaults to 0.0.
iterations
Optional- The number of times the animation should repeat. Defaults to
1
, and can also take a value ofInfinity
to make it repeat for as long as the element exists.
Future Options
The following options are currently not shipped anywhere, but will be added in the near future:
composite
- Determines how values are combined between this animation and the element's underlying values.
iterationComposite
- Determines how values build from iteration to iteration in the current animation.
The second type of constructor (see above) creates a clone of an existing KeyframeEffectReadOnly
object instance. Its parameter is as follows:
- sourceKeyFrames
- A
KeyframeEffectReadOnly
object that you want to clone.
Examples
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 );
Specifications
Specification | Status | Comment |
---|---|---|
Web Animations The definition of 'keyframeEffect()' in that specification. |
Working Draft | Editor's draft. |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | No support | No support | No support |
composite and iterationComposite options |
No support | No support | No support | No support | No support |
Clone constructor (2nd type) | (Yes) | No support[1] | No support | No support | No support |
Feature | Android | Android Webview | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile | Chrome for Android |
---|---|---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | (Yes) | No support | No support | No support | (Yes) |
composite and iterationComposite options |
No support | No support | (Yes) | No support | No support | No support | No support |
Clone constructor (2nd type) | (Yes) | (Yes) | No support[1] | No support | No support | No support | (Yes) |
[1] Only enabled in Firefox 52 Nightly and Dev edition. Turned off in Beta/release.