jQuery实现带延迟动画的二级Tab切换下拉菜单

<!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>二级tab切换</title>
<style type="text/css">
 *{margin:0;padding:0;}
 body{padding:10px ;}
 #div1{background:#333;height:30px;width:400px;margin:0 0 10px 0;}
 #div1 li { width: 100px; float:left;line-height:30px; background: 333; margin:0 5px;list-style:none; text-align: center;}
 #div1 li a { color:#fff; text-decoration:none;font-size:12px; display:block;}
 #div1 li a:hover { text-decoration:underline;}
 #div1 li span { display: none;}
</style>
<script type="text/javascript" src="jquery-1.6.2.min.js"></script>
</head>
<body>
 <div id="div1">
   <ul id="nav">
    <li>
    <a href="#">menu1</a>
    <span><a href="#">111</a></span>
    </li>
    <li>
    <a href="#">menu2</a>
    <span><a href="#">222</a></span>
    </li>
    <li>
    <a href="#">menu3</a>
    <span><a href="#">CopyRight@</a></span>
    </li>
    </ul>
  </div>
</body>
<script type="text/javascript">
 $(document).ready(function() { 
 $("ul#nav li").hover(function() { //Hover over event on list item
 $(this).find("span").show(200).css({ 'background' : '#1376c9','display' : 'block'}); //Show the subnav
 } , function() { //on hover out...
 $(this).find("span").hide(200); //Hide the subnav
 });
 });
</script>
</html>