基于RAF的一个小动画框

RAF也即是requestAnimationFrame，之前的动画都是基于setTimeout写的，所以为了性能方面的考虑，开始使用requestAnimationFrame写动画。

function animation(obj, data) {if (obj.timer) {window.cancelAnimationFrame(obj.timer)}obj.timer = window.requestAnimationFrame(function () {for (var i in data) {var current=parseInt(obj.style[i]);var target=parseInt(data[i]);var speed=(target-current)/8;speed=speed>0?Math.ceil(speed):Math.floor(speed);if(current!=target){obj.style[i]=current+speed+"px";obj.timer=window.requestAnimationFrame(arguments.callee);}}})
}