Transition end stuff

whichTransition.js

function whichTransitionEvent() {
    var t,
        $e = document.createElement('whatever'),
        transitions = {
            'transition': 'transitionend',
            'OTransition': 'oTransitionEnd',
            'MozTransition': 'transitionend',
            'WebkitTransition': 'webkitTransitionEnd'
        };

    for (t in transitions) {
        if ($e.style[t] !== undefined) {
            return transitions[t];
        }
    }
}