新锐浏览器也为此添加了一个事件,当渐变动画结束时,让我们清除渐变属性。不过，这个事件名，非常不规则，webkit系是webkitTransitionEnd，opera是oTransition，FF竟然是transitionend!它们与CSS属性那个大写开头的驼峰风格是不一样的(如WebkitTransition,OTransition,MozTransition)

var transitionEnd = (navigator.vendor && "webkitTransitionEnd") || ( window.opera && "oTransitionEnd") || "transitionend"; 
el.addEventListener(transitionEnd,function(){//IE10 pp3将会支持transition与transform 
            //http://blogs.msdn.com/b/ie/archive/2011/04/12/native-html5-first-ie10-platform-preview-available-for-download.aspx 
     this.style.removeProperty(css3transition.replace( rupper, "-$1" ).toLowerCase());//css3transition即WebkitTransition等 
},true)