This listens for the end of an element's CSS transition event.

cssTransitionEnd.js

		(function() {
			var e = document.getElementsByClassName('sample')[0];
			
			function whichTransitionEvent(){
			    var t;
			    var el = document.createElement('fakeelement');
			    var transitions = {
			      'transition':'transitionend',
			      'OTransition':'oTransitionEnd',
			      'MozTransition':'transitionend',
			      'WebkitTransition':'webkitTransitionEnd'
			  };
			    for (t in transitions){
			        if (el.style[t] !== undefined) {
			            return transitions[t];
			        }
			    }
			};

			var transitionEvent = whichTransitionEvent();
			transitionEvent && e.addEventListener(transitionEvent, function() {
				console.log('Transition complete!  This is the callback, no library needed!');
			});

			startFade = function() {
				e.className+= ' hide';
			}
		})();