js带记忆功能伸缩菜单的IE6兼容？ - 编程论坛

大家好：下面是一个很好用的带记忆功能伸缩菜单，适用于未使用框架结构网站后台页面，但是在IE6下无法记忆菜单的展开状态，哪位高手能修改一下，让它也兼容IE6?

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.
<html xmlns="http://www.
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>带记忆功能的伸缩菜单</title>
</head>

<body>
<ul>
    <li>
        <a href="javascript:;" onclick="show('ol1')">国内新闻</a>
        <ol class="itemmenu" id="ol1" style="display:none;">
            <li><a href="#">A</a></li>
            <li><a href="#">B</a></li>
            <li><a href="#">C</a></li>
        </ol>
    </li>
    <li>
        <a href="javascript:;" onclick="show('ol2')">国际新闻</a>
         <ol class="itemmenu" id="ol2" style="display:none;">
            <li><a href="#">D</a></li>
            <li><a href="#">E</a></li>
            <li><a href="#">F</a></li>
        </ol>
   </li>
    <li>
        <a href="javascript:;" onclick="show('ol3')">宇宙新闻</a>
         <ol class="itemmenu" id="ol3" style="display:none;">
            <li><a href="#">G</a></li>
            <li><a href="#">H</a></li>
            <li><a href="#">I</a></li>
        </ol>
    </li>
</ul>
</body>
</html>
<script language="javascript" type="text/javascript">
function $(obj){
    return document.getElementById(obj);
}
//初始化左边菜单
function setCookie(sName,sValue,expireHours) {
    var cookieString = sName + "=" + escape(sValue);
    //;判断是否设置过期时间
    if (expireHours>0) {
         var date = new Date();
         date.setTime(date.getTime + expireHours * 3600 * 1000);
         cookieString = cookieString + "; expire=" + date.toGMTString();
    }
    document.cookie = cookieString;
}
//--- 获取cookie
function getCookie(sName) {
  var aCookie = document.cookie.split("; ");
  for (var j=0; j < aCookie.length; j++){
    var aCrumb = aCookie[j].split("=");
    if (escape(sName) == aCrumb[0])
      return unescape(aCrumb[1]);
  }
  return null;
}
document.getElementsByClassName = function(cl) {
    var retnode = [];
    var myclass = new RegExp('\\b'+cl+'\\b');
    var elem = this.getElementsByTagName('*');
    for (var j = 0; j < elem.length; j++) {
        var classes = elem[j].className;
        if (myclass.test(classes)) retnode.push(elem[j]);
    }
    return retnode;
}
function show(obj){
    if($(obj).style.display == "none"){
        $(obj).style.display = "block";
    }else{
        $(obj).style.display = "none";
    }
    setAllItemCookie();
}
function setAllItemCookie(){
    //遍历菜单入库操作
    var strCookieMenu = "";
    var items = document.getElementsByClassName("itemmenu");
    for(var i = 0;i<items.length;i++){
        if(items[i].style.display=="block"){
            strCookieMenu += items[i].id + ",";
        }
    }
    setCookie("product-menu",strCookieMenu,1);
}

window.onload = function(){
    //初始化菜单
    try
    {
        var currMenu = getCookie("product-menu");
        var arrMenu = currMenu.split(",");
        for(var i = 0;i < arrMenu.length;i++){
            $(arrMenu[i]).style.display = "block";
        }
    }
    catch(e)
    {
    }


}
</script>