帮忙看一下怎么不可以啊，谢谢
<!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 type="text/css">
body,ul,li{ list-style: none; margin: 0; padding: 0;}
li{ width: 200px; height: 200px; background:red; margin-bottom:1px;
filter:alpha(opacity:30);opacity:0.3; float:left; margin-right:10px;}
</style>
</head>
<body>
<ul>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
</ul>
</body>
</html>
<script type="text/javascript">
var ali = document.getElementsByTagName('li');
for (var i = 0; i < ali.length; i++) {
ali[i].timer = null;
ali[i].alpha = 30;
ali[i].onmouseover = function(){
opty(this,100);
}
ali[i].onmouseout = function(){
opty(this,30);
}
};
//var timer = null;
//var alpha =0 ;
function opty(obj,iTarget){
obj.timer = setInterval(function(){
var speed = 0;
if(obj.alpha>iTarget){
speed = -5;
}else{
speed = 5;
};
if(obj.alpha == iTarget){
clearInterval(obj.timer);
}else{
obj.alpha+=speed;
obj.style.filter = 'alpha(opacity:'+obj.alpha+')';
obj.style.opacity = obj.alpha/100;
}
},30)
}
</script>帮忙看一下怎么不可以啊，谢谢
