请教一个Jquery下拉菜单的问题

从网上找了一个JQ菜单的例子，不过是二级的，我想把他改成三级的，不太会用JQ，修改后发现IE6下移动到三级菜单上以后整个下拉会有闪烁的情况，请各位帮帮看看是哪里的问题，谢谢

复制代码 <script type="text/javascript" src="http://jqueryjs.googlecode.com/files/jquery-1.3.2.min.js"></script> <script> var ddmenuitem,ddmenuitem2 = 0; function jsddm_open() {      jsddm_close();    ddmenuitem = $(this).find('ul:eq(0)').css('visibility', 'visible');        $(this).find('ul:eq(0) > li').bind('mouseover', jsddm_open2);     $(this).find('ul:eq(0) > li').bind('mouseout', jsddm_close2);          } function jsddm_close() { if(ddmenuitem) ddmenuitem.css('visibility', 'hidden'); } $(document).ready(function() {  $('#jsddm > li').bind('mouseover', jsddm_open)    $('#jsddm > li').bind('mouseout',  jsddm_close)}    );    function jsddm_open2() {      ddmenuitem2 = $(this).find('ul').css('visibility', 'visible');    }    function jsddm_close2() {  if(ddmenuitem2) ddmenuitem2.css('visibility', 'hidden'); } </script>     <style type="text/css">     #jsddm {    margin: 0;     padding: 0}          #jsddm li     {    float: left;         list-style: none;         font: 12px Tahoma, Arial}     #jsddm li a     {    display: block;         background: #20548E;         padding: 5px 12px;         text-decoration: none;         border-right: 1px solid white;         width: 170px;         color: #EAFFED;         height:50px; }              #jsddm li a:hover     {    background: #1A4473}                  #jsddm li ul         {    margin: 0;             padding: 0;             position: absolute;             visibility: hidden;             border-top: 1px solid white}                  #jsddm li ul li         {    float: none;             display: inline}                  #jsddm li ul li a         {    width: 160px;             background: #9F1B1B}                  #jsddm li ul li a:hover         {    background: #7F1616; }         #jsddm li ul li ul{ margin-left:160px; margin-top:-51px;visibility: hidden;} </style> <ul id="jsddm">     <li><a href="#" style="width:400px;">1</a>         <ul>             <li><a href="#">1.1</a><ul>             <li><a href="#">1.1.1</a></li>             <li><a href="#">1.1.2</a></li>             <li><a href="#">1.1.3</a></li>         </ul></li>             <li><a href="#">1.2</a></li>             <li><a href="#">1.3</a></li>         </ul>     </li>     <li>1</li>     <li><a href="#">2</a>         <ul>             <li><a href="#">2.1</a><ul>             <li><a href="#">2.1.2</a></li>             <li><a href="#">2.1.3</a></li>         </ul></li>             <li><a href="#">2.2</a></li>             <li><a href="#">2.3</a></li>         </ul>     </li>     <li><a href="#">3</a><ul><li><a href="#">3</a></li><li><a href="#">3</a></li></ul></li>     <li><a href="#">4</a></li>     <li><a href="#">5</a></li> </ul>