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

The setKeyframes() method of the KeyframeEffect interface replaces the keyframes that make up the affected KeyframeEffect with a new set of keyframes.




A keyframe object or null. If set to null, the keyframes are replaced with a sequence of empty keyframes.

There are two different ways to format keyframes:

  1. An array of objects (keyframes) consisting of properties and values to iterate over. This is the canonical format returned by the getKeyframes() method.

      { // from
        opacity: 0,
        color: "#fff"
      { // to
        opacity: 1,
        color: "#000"
    ], 2000);

    Offsets for each keyframe can be specified by providing an offset value.

    element.animate([ { opacity: 1 },
                      { opacity: 0.1, offset: 0.7 },
                      { opacity: 0 } ],

    Note: offset values, if provided, must be between 0.0 and 1.0 (inclusive) and arranged in ascending order.

    It is not necessary to specify an offset for every keyframe. Keyframes without a specified offset will be evenly spaced between adjacent keyframes.

    The easing to apply between keyframes can be specified by providing an easing value as illustrated below.

    element.animate([ { opacity: 1, easing: 'ease-out' },
                      { opacity: 0.1, easing: 'ease-in' },
                      { opacity: 0 } ],

    In this example, the specified easing only applies from the keyframe where it is specified until the next keyframe. Any easing value specified on the options argument, however, applies across a single iteration of the animation — for the entire duration.

  2. An object containing key-value pairs consisting of the property to animate and an array of values to iterate over.

      opacity: [ 0, 1 ],          // [ from, to ]
      color:   [ "#fff", "#000" ] // [ from, to ]
    }, 2000);

    Using this format, the number of elements in each array does not need to be equal. The provided values will be spaced out independently.

      opacity: [ 0, 1 ], // offset: 0, 1
      backgroundColor: [ "red", "yellow", "green" ], // offset: 0, 0.5, 1
    }, 2000);

    The special keys offset, easing, and composite (described below) may be specified alongside the property values.

      opacity: [ 0, 0.9, 1 ],
      offset: [ 0, 0.8 ], // Shorthand for [ 0, 0.8, 1 ]
      easing: [ 'ease-in', 'ease-out' ],
    }, 2000);

    After generating a suitable set of keyframes from the property value lists, each supplied offset is applied to the corresponding keyframe. If there are insufficient values, or if the list contains null values, the keyframes without specified offsets will be evenly spaced as with the array format described above.

    If there are too few easing or composite values, the corresponding list will be repeated as needed.

Implicit to/from keyframes

In newer browser versions, you are able to set a beginning or end state for an animation only (i.e. a single keyframe), and the browser will infer the other end of the animation if it is able to. For example, consider this simple animation — the Keyframe object looks like so:

let rotate360 = [
  { transform: 'rotate(360deg)' }

We have only specified the end state of the animation, and the beginning state is implied.

Return value



Exception Explanation
TypeError One or more of the frames were not of the correct type of object, the keyframes were not loosely sorted by offset, or a keyframe existed with an offset of less than 0 or more than 1.

Note: If the keyframes cannot be processed or are malformed, the KeyframeEffect's keyframes are not modified.


// passing an array of keyframe objects
  { color: 'blue' },
    { color: 'green', left: '10px' }

// passing an object with arrays for values
    color: ['blue', 'green'],
    left: [ '0', '10px']

// passing a single-member object
    color: 'blue'


Web Animations Level 2 (Web Animations 2)
# dom-keyframeeffect-setkeyframes

Browser compatibility

BCD tables only load in the browser

See also