WebKitTransitionEvent
WebKitTransitionEvent objects provide information about CSS transitions specified using the transition property. An event is sent at the end of a transition for each CSS property in the transition. Each event contains the name of the CSS property and duration of the transition. You can use these events to perform some action that starts at the end of a transition.
Declaration
interface WebKitTransitionEventOverview
For more on CSS transition events, see https://www.w3.org/TR/css3-transitions/#transition-events.