鼠標(biāo)滑過(guò)沒有任何效果，求告知哪里錯(cuò)了

?var a=document.getElementsByTagName("div");

? for(var i=0;i<a.length;i++)

? {

? a[i].onmouseover=function()

? {

?var _this=this.getElementsByTagName("img")[0];

?startMove(_this,{top:-15});

}

? }

? function startMove(obj,json,f)

?{

?clearInterval(obj.time);

var flag=true;

?obj.time=setInterval(function(){

for(var kind in json)

{

var attribute=parseInt(getStyle(obj,kind));

var speed=(json[kind]-attribute)/10;

speed=speed>0?Math.ceil(speed):Math.floor(speed);

if(attribute!=json[kind])

{

flag=false;

obj.style[kind]=attribute+speed+"px";

}

if(flag)

{

clearInterval(obj.time);

if(f)

f();

}

}

},30);}

?function getStyle(obj,attr)

?{

?if(obj.currentStyle)

?return obj.currentStyle[attr];

?else

?return obj.getComputedStyle(obj,false)[attr];

?}