CSSTransition: transitionProperty property

The transitionProperty property of the CSSTransition interface returns the expanded transition property name of the transition. This is the longhand CSS property for which the transition was generated.

Value

A string.

Examples

undefined

Returning the transitionProperty

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. The transitionProperty property returns the property that the transition is created for, which is width.

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

.box:hover {
  width: 200px;
}
js
const item = document.querySelector(".box");
item.addEventListener("transitionrun", () => {
  let animations = document.querySelector(".box").getAnimations();
  console.log(animations[0].propertyName);
});

Specifications