如何跨浏览器标准化CSS3转换结束事件？

Webkit的转换结束事件称为webkitTransitionEnd，Firefox为TransitionEnd，Opera为oTransformtionEnd。用纯JS解决所有这些问题的好方法是什么？我应该做浏览器嗅探吗？或者单独实现每一个？有没有其他我没想到的方式？

即：

//doing browser sniffing
var transitionend = (isSafari) ? "webkitTransitionEnd" : (isFirefox) ? "transitionEnd" : (isOpera) ? "oTransitionEnd";

element.addEventListener(transitionend, function(){
  //do whatever
},false);

或

// Assigning an event listener per browser
element.addEventListener("webkitTransitionEnd", fn);
element.addEventListener("oTransitionEnd", fn);
element.addEventListener("transitionEnd", fn);

function fn() {
   //do whatever
}

---

解决方案

Modelnizr中使用了一种改进的技术：

function transitionEndEventName () {
    var i,
        undefined,
        el = document.createElement('div'),
        transitions = {
            'transition':'transitionend',
            'OTransition':'otransitionend',  // oTransitionEnd in very old Opera
            'MozTransition':'transitionend',
            'WebkitTransition':'webkitTransitionEnd'
        };

    for (i in transitions) {
        if (transitions.hasOwnProperty(i) && el.style[i] !== undefined) {
            return transitions[i];
        }
    }

    //TODO: throw 'TransitionEnd event is not supported in this browser'; 
}

然后，只要需要转换结束事件，您就可以调用此函数：

var transitionEnd = transitionEndEventName();
element.addEventListener(transitionEnd, theFunctionToInvoke, false);