为什么我的程序没有效果，求指导！
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"/>
<style type="text/css">
*{
margin:0;
padding:0;
}
ul,li{
list-style:none;
}
ul li{
width:200px;
height:100px;
background:yellow;
margin-bottom:20px;
}
</style>
<script>
window.onload=function(){
var aLi=document.getElementsByTagName('li');
for(var i=0;i<aLi.length;i++){
aLi[i].onmouseover=function(){
startMove(this,400);
}
aLi[i].onmouseout=function(){
startMove(this,200);
}
}
}
var timer=null;
function startMove(obj,iTarget){
clearInterval(timer);
timer=setInterval(function(){
var speed=(iTarget-obj.offsetWidth)/8;
speed=speed>0?Math.ceil(speed):Math.floor(speed);
if(obj.offsetWidth==iTarget){
clearInterval(timer);
}else{
obj.style.width=obj.oddsetWidth+speed+'px';
}
},30)
}
</script>
</head>
<body>
<ul>
<li></li>
<li></li>
<li></li>
</ul>
</body>
</html>
