图片列表：鼠标移入/移出改变图片透明度
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="content-type" content="text/html" charset="utf-8">
<title>
列表
</title>
<style>
ul li{
margin:none;
padding:none;
list-style-type: none;
}
#list ul li.ab img{
opacity: 0.3;
filter:alpha(opacity=30);
cursor: pointer;
}
#list ul li img{
opacity:1;
filter:alpha(opacity=100);
cursor: crosshair;
}
</style>
</head>
<body>
<div id="list">
<ul>
<li><img src="1.jpg" alt="这是个图片" id="pic1" title="图"></li>
</ul>
</div>
</body>
<script type="text/javascript">
window.onload=function () {
var as=document.getElementsByTagName("li");
for(var a=0;a<as.length; a++)
{
as[a].onmouseover=function (){
this.className="ab";
};
as[a].onmouseout=function (){
this.className="";
}
}
}
</script>
</html>