jquery中如何实现菜单的展开和折叠（代码）

<script>
$(function () {
$("dl dt").click(function () {
$(this).siblings().toggle().parent().siblings().children("dd").hide();
});
});
</script>

<dl id="ctl00_menuPassMgr">
 <dt><span>
<img alt="" src='images/ico03.gif' />
</span> 
<span>
<a href="javascript:">密码管理</a></span>
 </dt>
 <dd>
 <span>
<img alt="" src='images/ico06.gif' /></span> <span>
<a href='/SysManager/ChangePassword.aspx'>修改密码</a></span>
 </dd>
 </dl>
 <dl id="ctl00_menuHourse">
 <dt><span>

 <img alt="" src='images/ico03.gif' 
/></span> <span><a 
href="javascript:">宿舍管理</a></span>
 </dt>
 <dd>
 <span>

 <img alt="" src='images/ico06.gif' 
/></span> <span><a 
href='/SchoolHourseManager/SchoolHourseList.aspx'>
 学生宿舍查询</a></span>
 </dd>
 <dd>
 <span>

 <img alt="" src='images/ico06.gif' 
/></span> <span><a 
href='/SchoolHourseManager/SchoolHourseEdit.aspx'>
 学生宿舍新增</a></span>
 </dd>
 <dd>
 <span>

 <img alt="" src='images/ico06.gif' 
/></span> <span><a 
href='/SchoolHourseManager/CheckStudentDormitory.aspx'>
 学生宿舍分配</a></span>
 </dd>
 </dl>
 <dl id="ctl00_menuStudent">
 <dt><span>

 <img alt="" src='images/ico03.gif' 
/></span> <span><a 
href="javascript:">学生管理</a></span>
 </dt>
 <dd>
 <span>

 <img alt="" src='images/ico06.gif' 
/></span> <span><a 
href='/StudentManager/StudentList.aspx'>
 学生信息列表</a></span>
 </dd>
 <dd>
 <span>

 <img alt="" src='images/ico06.gif' 
/></span> <span><a 
href='/StudentManager/StudentEdit.aspx'>
 学生信息新增</a></span>
 </dd>
 <dd>
 <span>

 <img alt="" src='images/ico06.gif' 
/></span> <span><a 
href='/ClassManager/ClassList.aspx'>
 班级信息列表</a></span>
 </dd>
 <dd>
 <span>

 <img alt="" src='images/ico06.gif' 
/></span> <span><a 
href='/ClassManager/ClassEdit.aspx'>
 班级信息新增</a></span>
 </dd>
 </dl>
 <dl id="ctl00_menuTeacher">
 <dt><span>

 <img alt="" src='images/ico03.gif' 
/></span> <span><a 
href="javascript:">教师管理</a></span>
 </dt>
 <dd>
 <span>

 <img alt="" src='images/ico06.gif' 
/></span> <span><a 
href='/TeacherManager/TeacherEdit.aspx'>
 教师入职登记</a></span>
 </dd>
 <dd>
 <span>

 <img alt="" src='images/ico06.gif' 
/></span> <span><a 
href='/TeacherManager/TeacherList.aspx'>
 教师信息查询</a></span>
 </dd>
 </dl>
 <dl id="ctl00_menuReport">
 <dt><span>

 <img alt="" src='images/ico03.gif' 
/></span> <span><a 
href="javascript:">缴费及统计报表</a></span>
 </dt>
 <dd>
 <span>

 <img alt="" src='images/ico06.gif' 
/></span> <span><a 
href='/TeacherManager/TeacherList.aspx'>
 学生缴费入口</a></span>
 </dd>
 <dd>
 <span>

 <img alt="" src='images/ico06.gif' 
/></span> <span><a 
href='/TeacherManager/TeacherList.aspx'>
 学生缴费查询</a></span>
 </dd>
 <dd>
 <span>

 <img alt="" src='images/ico06.gif' 
/></span> <span><a 
href='/TeacherManager/TeacherList.aspx'>
 收件信息查看</a></span>
 </dd>
 <dd>
 <span>

 <img alt="" src='images/ico06.gif' 
/></span> <span><a 
href='/TeacherManager/TeacherList.aspx'>
 发件信息查看</a></span>
 </dd>
 </dl>