                        课程
                    
                        /前端开发
                        
                            /JavaScript
                        
                        /JS动画效果

为何没反应？

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style>
*{ 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.getElementsByName('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.offsetWidth+speed+'px';	
				}
		
		},30)
	}
</script>
</head>

<body>
<ul>
   <li></li>
   <li></li>
   <li></li>

</ul>
</body>
</html>