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

This interface inherits properties from its parent, Animation.

CSSTransition.transitionProperty Read only

Returns the transition CSS property name as a string.

This interface inherits methods from its parent, Animation.

No specific methods.

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();
  console.log(animations[0]);
});