KeyframeEffect.KeyframeEffect()

The KeyframeEffect() constructor of the Web Animations API returns a new KeyframeEffect object instance.

Syntax

var keyframes = new keyframeEffect(element, keyframeSet, keyframeOptions);

Parameters

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:

AnimationEffectTimingProperties.delay Optional

The number of milliseconds to delay the start of the animation. Defaults to 0.

AnimationEffectTimingProperties.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.

AnimationEffectTimingProperties.duration Optional

The number of milliseconds each iteration of the animation takes to complete. Defaults to 0.

AnimationEffectTimingProperties.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.

AnimationEffectTimingProperties.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. 

AnimationEffectTimingProperties.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), or both. Defaults to none.

AnimationEffectTimingProperties.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.

AnimationEffectTimingProperties.iterations Optional

The number of times the animation should repeat. Defaults to 1, and can also take a value of infinity to make it repeat infinitely.

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.

spacing

Determines how keyframes without temporal offsets should be distributed during the animation's duration.

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

Browser compatibility

See also

• KeyframeEffect Interface
• Web Animations API
• Animation