JS左侧菜单问题

用ASP.NET搭建了MasterPage模版页.然后在MasterPage左侧使用了菜单.
只能在主页显示正常,点击其它页面显示错误.代码如下:
<HEAD>
<TITLE>学生综合素质测评系统</TITLE>
<META http-equiv=Content-Type content="text/html; charset=gb2312">
<META content="MSHTML 6.00.6000.16705" name=GENERATOR>
<link rel="stylesheet" href="css/sdmenu/sdmenu.css" type="text/css"/>
<script src="js/sdmenu.js" type=text/javascript></script>
<script type="text/javascript"> var myMenu;
window.onload = function() {
myMenu = new SDMenu("my_menu");
myMenu.init();
};</script>
</HEAD>
<div style="float: left" id="my_menu" class="sdmenu">
      <div>
        <span>Online Tools</span>
        <a href="http://tools.dynamicdrive.com/imageoptimizer/">Image Optimizer</a>
        <a href="http://tools.dynamicdrive.com/favicon/">FavIcon Generator</a>
        <a href="http://www.dynamicdrive.com/emailriddler/">Email Riddler</a>
        <a href="http://tools.dynamicdrive.com/password/">htaccess Password</a>
        <a href="http://tools.dynamicdrive.com/gradient/">Gradient Image</a>
        <a href="http://tools.dynamicdrive.com/button/">Button Maker</a>
      </div>
      <div>
        <span>Support Us</span>
        <a href="http://www.dynamicdrive.com/recommendit/">Recommend Us</a>
        <a href="http://www.dynamicdrive.com/link.htm">Link to Us</a>
        <a href="http://www.dynamicdrive.com/resources/">Web Resources</a>
      </div>
      <div class="collapsed">
        <span>Partners</span>
        <a href="http://www.javascriptkit.com">JavaScript Kit</a>
        <a href="http://www.cssdrive.com">CSS Drive</a>
        <a href="http://www.codingforums.com">CodingForums</a>
        <a href="http://www.dynamicdrive.com/style/">CSS Examples</a>
      </div>
      <div>
        <span>Test Current</span>
        <a href="?foo=bar">Current or not</a>
        <a href="./">Current or not</a>
        <a href="index.html">Current or not</a>
        <a href="index.html?query">Current or not</a>
      </div>
    </div>