<!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>測試</title>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>
<script type="text/javascript">
$(function(){
$("#menu li").hover(function(){
$(this).addClass("curr").find("ul:first").show();
},function(){
$(this).removeClass("curr").find("ul:first").hide();
});
});
</script>
<style type="text/css">
ul { margin:0;padding:0; }
#menu { width: 100px;background: #c60;}
#menu li { list-style:none; position: relative; width: 100px; }
li ul{ display: none; position: absolute; left: 100px; top:0; background: #ccc; }
ul li:hover, ul li.curr { background: #f60; }
</style>
</head>
<body>
<div id="page">
<ul id="menu">
<li>
菜單111111
<ul>
<li>子菜單333
<ul>
<li>子菜單444
<ul>
<li>子菜單444</li>
<li>子菜單444</li>
<li>子菜單444</li>
<li>子菜單444</li>
</ul>
</li>
</ul>
</li>
<li>子菜單22222</li>
</ul>
</li>
<li>
菜單2222
<ul>
<li>子菜單333
<ul>
<li>子菜單333</li>
<li>子菜單333</li>
<li>子菜單333</li>
<li>子菜單333</li>
</ul>
</li>
<li>子菜單22222</li>
<li>子菜單333
<ul>
<li>子菜單333</li>
<li>子菜單333</li>
<li>子菜單333</li>
<li>子菜單333</li>
</ul>
</li>
</ul>
</li>
</ul>
</div>
</body>
</html>
show()和hide()可以寫成其他效果，比如fadeIn,fadeOut，或者animate自定義。