CSS transition event(s)

TransitionEvent is a simple bridge between CSS transitions and javascript. Javascript events are emitted by the browser when a (part of a) CSS transition ends. This can be usefull in some cases where say Web Animations perhaps is not an option. Here I am using TransitionEnd to display the end css properties in the eventlog. The stopped/running button is controled using mouseEnter and mouseLeave event. Unfortunally the TransitionStart event I could not get my browser to emit...