我有这个导航菜单：
http://jsfiddle.net/laziale/T45tD/4/
我想知道如何修复导航菜单可通过子菜单扩展的菜单。我输入了一些样本数据。
这是源代码：
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<link type="text/css" rel="stylesheet" href="App_Themes/Main/style.css" />
<link type="text/css" rel="stylesheet" href="App_Themes/Main/reset.css" />
<link rel="stylesheet" href="http://code.jquery.com/ui/1.9.2/themes/base/jquery-ui.css" />
<script src="http://code.jquery.com/jquery-1.8.3.js"></script>
<script src="http://code.jquery.com/ui/1.9.2/jquery-ui.js"></script>
</head>
<body>
<form id="form1" runat="server">
<div class="pagetop">
<div class="head pagesize">
<div class="head_top">
<div class="topbuts">
<ul class="clear">
</ul>
</div>
<div class="user clear">
<span class="user-detail">
</span>
</div>
<div class="logo clear">
<a href="#" title="Home">
<img src="Images/logo.jpg" class="picture" />
<span class="textlogo">
</span>
</a>
</div>
</div>
<div class="menu">
<ul class="clear">
<li class="active"><a href="#">Client</a>
<ul>
<li class="subNav"><a href="#">Client Summary</a></li>
</ul>
</li>
<li><a href="#">Agent</a>
<ul>
<li class="subNav"><a href="#">Agent Summary</a>
<ul>
<li class="subNav"><a href="#">Link1y</a></li>
<li class="subNav"><a href="#">Link2</a></li>
</ul></li>
</ul>
</li>
<li><a href="#">System Utility</a>
<ul>
<li class="subNav"><a href="#">Link1</a>
<li class="subNav"><a href="#">Link2</a>
<li class="subNav"><a href="#">Link3</a>
</ul>
</li>
<li><a href="#">Report</a></li>
<li><a href="#">Maintenance</a></li>
<li><a href="#">About Us</a></li>
<li><a href="#">Contact Us</a></li>
</ul>
</div>
</div>
</div>
<div>
</div>
</form>
</body>
</html>
和CSS：
body {
min-width:1000px;
text-align:center;
margin:0px;
font-family:Arial;
font-size:12px;
color:#666666;
background:#8D8D8D;
}
.pagetop {
width:100%;
min-width:1000px;
background-color: #333333;
border-bottom: 4px solid #007FAA;
position:relative;
z-index:100;
min-height:149px;
}
.head_top {
position:relative;
min-height:114px;
}
.topbuts {
position:absolute;
top:0px;
right:0px;
}
.topbuts ul {
float:right;
}
.topbuts li {
float:left;
margin-left:2px;
font-size:11px;
font-weight: bold;
}
.topbuts li a {
background:#007FAA;
text-decoration:none;
display:block;
color:#FFFFFF;
line-height:16px;
padding:1px 12px 2px 12px;
}
ol ul {
list-style:none;
}
.head {
padding:0px;
}
.pagesize {
width:1000px;
margin: 0px auto;
text-align:left;
}
.user {
clear:both;
float:right;
padding-top:27px;
}
.user-detail {
display: block;
float:right;
text-align:right;
}
.user-detail .name {
display: block;
line-height:normal;
text-align:left;
float:right;
font-size:18px;color:#FFFFFF;
padding:2px 0px 7px 0px;
}
.user-detail .text {
color: #bbbbbb;
clear:both;
font-size:11px;
line-height:18px;
color:#FFFFFF;
display:block;
}
.logo {
padding-top:20px;
}
.logo a {
text-decoration:none;
}
.logo .picture {
float:left;
margin-right:10px;
}
.logo .textlogo {
float:left;
}
.logo .title {
display:block;
font-family:Arial;
font-size:20px;
color:#FFFFFF;
font-weight: bold;
margin-top:5px;
letter-spacing: -0.02em;
}
.logo .text {
display:block;
font-weight: bold;
color: #BBBBBB;
position:relative;
top: -2px;
}
.menu ul {
font-size:13px;
}
.menu li {
float:left;
margin-right:3px;
padding-bottom:5px;
position:relative;
}
.menu li .active a {
background: #FFFFFF;
color: #333333;
text-shadow: 1px 1px 1px #BBBBBB;
}
.menu li a {
display:block;
line-height:16px;
padding: 7px 15px 7px 5px;
color: #FFFFFF;
text-decoration:none;
font-weight:bold;
text-shadow: 1px 1px 1px #333333;
-moz-border-radius: 3px 3px 3px 3px;
-webkit-border-radius: 3px 3px 3px 3px;
border-radius: 3px 3px 3px 3px;
background:url('..images/button_glas1.png') center center repeat-x #555555;
}
a {
color: #006577;
text-decoration:none;
}