The CSSTransition interface of the Web Animations API represents an Animation object used for a CSS Transition.

EventTarget Animation CSSTransition

Instance properties

Inherits properties from its ancestor Animation and adds transitionProperty.

CSSTransition.transitionProperty Read only

Returns the transition CSS property name as a string.

Event handlers

No specific event handlers; inherits methods from its ancestor Animation.

Instance methods

No specific methods; inherits methods from its ancestor Animation.


Inspecting the returned CSSTransition

The transition in the following example changes the width of the box on hover. Calling Element.getAnimations() returns an array of all Animation objects. In our case this returns a CSSTransition object, representing the animation created.

.box {
  background-color: #165baa;
  color: #fff;
  width: 100px;
  height: 100px;
  transition: width 4s;

.box:hover {
  width: 200px;
const item = document.querySelector(".box");
item.addEventListener('transitionrun', () => {
  let animations = document.querySelector(".box").getAnimations();


CSS Transitions Level 2
# the-CSSTransition-interface

Browser compatibility

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