求助一个CSS+JS的导航栏问题，在线等，即时结贴~~~~~~~~~~~~~~~~~~~

源代码如下，想实现的就是，鼠标点击“政务公开”等标题时，切换到该标签，同时背景图片显示到该标签<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>top</title>
<link href="skin/css/base.css" rel="stylesheet" type="text/css">
<script language='javascript'>
var preFrameW = '206,*';
var FrameHide = 0;
var curStyle = 1;
var totalItem = 9;
function ChangeMenu(way){
var addwidth = 10;
var fcol = top.document.all.btFrame.cols;
if(way==1) addwidth = 10;
else if(way==-1) addwidth = -10;
else if(way==0){
if(FrameHide == 0){
preFrameW = top.document.all.btFrame.cols;
top.document.all.btFrame.cols = '0,*';
FrameHide = 1;
return;
}else{
top.document.all.btFrame.cols = preFrameW;
FrameHide = 0;
return;
}
}
fcols = fcol.split(',');
fcols[0] = parseInt(fcols[0]) + addwidth;
top.document.all.btFrame.cols = fcols[0]+',*';
}
function mv(selobj,moveout,itemnum)
{
   if(itemnum==curStyle) return false;
   if(moveout=='m') selobj.className = 'itemsel';
   if(moveout=='o') selobj.className = 'item';
   return true;
}function changeSel(itemnum)
{
  curStyle = itemnum;
  for(i=1;i<=totalItem;i++)
  {
     if(document.getElementById('item'+i)) document.getElementById('item'+i).className='item';
  }
  document.getElementById('item'+itemnum).className='itemsel';
}</script>
<style>
/*---------------------页面基础定义----------------------------------*/
body,td,th {font-family: Tahoma, Verdana, Arial, sans-serif;font-size: 12px;color: #333333;}
body {margin-left: 0px;margin-top: 0px;margin-right: 0px;margin-bottom: 0px;}
/*---------------------链接定义----------------------------------*/
a {color: #333333;text-decoration: none;}
a:hover {color: #FF0000;text-decoration: none;}
a:active{color: #FF0000;text-decoration: none;}
/*---------------------菜单样式----------------------------------*/
#menu{height:32px;margin-top:8px; background-color:#990000;}
#menu ul{margin:auto; width:778px; height:32px;list-style-type:none; padding:0px; margin-top:0px; margin-bottom:0px;}
.m_li{float:left; width:114px; line-height:32px;  text-align:center; margin-right:-2px; margin-left:-2px;}
.m_li a{display:block; color:#FFFFFF; width:114px;}.m_line{float:left; width:1px; height:32px;line-height:32px;}   /*ff下有效(图片垂直居中)*/
.m_line img{margin-top:expression(( 32 - this.height ) / 2);}   /*ie下有效(图片垂直居中)*/.m_li_a{float:left; width:114px; line-height:32px; text-align:center; padding-top:3px; font-weight:bold;background-image:url(images/menu_bg.jpg); position:relative; height:32px; margin-top:-3px; margin-right:-2px; margin-left:-2px;}
.m_li_a a{display:block; color:#FF0000; width:114px;}
.smenu{width:774px; margin:0px auto 0px auto; padding:0px; list-style-type:none; height:32px;}
.s_li{line-height:32px; width:auto; display:none; height:32px; }
.s_li_a{line-height:32px; width:auto; display:block; height:32px; }
#tpa {margin:auto; width:978px;list-style-type:none; margin-top:-36px; margin-bottom:-10px;/*color: #009933; margin-top:-3px; margin-left:50px*/}#tpa dd {margin:0px;padding:0px;float:left;/*background:url(images/line2.jpg)*/}div.item{float:left; width:114px; line-height:36px;text-align:center;}
*html .itemsel {height:36px;line-height:40px;}
.itemsel {width:114px;text-align:center;height:36px;line-height:44px; background-image:url(images/menu_bg1.jpg);}.item a:link, .item a:visited {font-size:12px;color: #FFFFFF;text-decoration: none;}
.itemsel a:hover {color: #FF0000;font-weight: bold;border-bottom:2px solid #990100;}
.itemsel a:link, .itemsel a:visited {font-size: 12px;color: #FF0000;text-decoration: none;font-weight: bold;}</style>
</head>
<body><div id="menu">
  <ul>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_1" class='m_li_a'><a href="#">财税首页</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_2" class='m_li' onmouseover='mover(2);' onmouseout='mout(2);'><a href="#">政务公开</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_3" class='m_li' onmouseover='mover(3);' onmouseout='mout(3);'><a href="#">网上办事</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_4" class='m_li' onmouseover='mover(4);' onmouseout='mout(4);'><a href="#">公告中心</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_5" class='m_li' onmouseover='mover(5);' onmouseout='mout(5);'><a href="#">法规中心</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_6" class='m_li' onmouseover='mover(6);' onmouseout='mout(6);'><a href="#">财税文化</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_7" class='m_li' onmouseover='mover(7);' onmouseout='mout(7);'><a href="#">专题宣传</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
  </ul>
</div>

        <table width="100%" border="0" cellpadding="0" cellspacing="0" bgcolor="#f1f1f1">
          <tr>
            <td> </td>
          </tr>
        </table>
</body>
</html>

解决方案 »

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<li id="m_2" class='m_li' onmouseover='mover(2);' onmouseout='mout(2)' onclick='mclick(2)'>
var nowtip='-1';
在js fuction mclick(v){
if(nowtip!='-1'){
document.getElementById(nowtip).cssStyle='m_li' ;
}
if(document.getElementById('m_'+v)){
document.getElementById('m_'+v).cssStyle='active_li';/*(现在标题的css样式名字)*/
nowtip='m_'+v;
}
}
}至于样式 .active_li{......要啥样写啥}
更正下：
js：
var nowtip='-1';function mclick(v){
for(i=0;i<100;i++){
if(document.getElementById('m_'+i))
document.getElementById('m_'+i).className='m_li';  /*各栏目的样式全部还原*/
}
if(document.getElementById('m_'+v)){
document.getElementById('m_'+v).className='active_li';  /*现在的栏目的css样式名字。是className不是cssStyle*/
document.getElementById('frmgo').src='go'+v+'.html';  /* 子框架iframe内容切换到该标签所代表的栏目。你也可以用链接来做<a href="go2.html" target="frmgo">政务公开</a>。 */
nowtip='m_'+v;
}
}function mover(v){
if(nowtip=='m_'+v) return;
//...
}function mout(v){
if(nowtip=='m_'+v) return;
//...
}样式：
.active_li{//现在栏目的标题的背景图片等等样式 }
页面：
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_2" class='m_li' onmouseover='mover(2);' onmouseout='mout(2);' onclick='mclick(2)'><a href="#">政务公开</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_3" class='m_li' onmouseover='mover(3);' onmouseout='mout(3);' onclick='mclick(3)' ><a href="#">网上办事</a></li>而子框架所载入的网页这样
go2.html内容
<script type="text/javascript">
parent.document.title=document.title;//使得整个网页的标题是内容的标题
</script>
不好意思，之前的发错了，应该是：
（演示地址是http://www.lanrentuku.com/down/js/daohang-538/）
依旧是想实现：鼠标点击某标签后（比如“政务公开”），背景会停留再该标签上<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<meta name="keywords" content="JS代码,菜单导航,JS广告代码,JS特效代码" />
<meta name="description" content="此代码内容为可跳转回首页的CSS二级联动菜单，属于站长常用代码，更多菜单导航代码请访问懒人图库JS代码频道。" />
<title>可跳转回首页的CSS二级联动菜单_懒人图库</title>
<link href="css/css.css" rel="stylesheet" type="text/css" />
<script>
//初始化
var def="1";
function mover(object){
  //主菜单
  var mm=document.getElementById("m_"+object);
  mm.className="m_li_a";
  //初始主菜单先隐藏效果
  if(def!=0){
    var mdef=document.getElementById("m_"+def);
    mdef.className="m_li";
  }
  //子菜单
  var ss=document.getElementById("s_"+object);
  ss.style.display="block";
  //初始子菜单先隐藏效果
  if(def!=0){
    var sdef=document.getElementById("s_"+def);
    sdef.style.display="none";
  }
}function mout(object){
  //主菜单
  var mm=document.getElementById("m_"+object);
  mm.className="m_li";
  //初始主菜单还原效果
  if(def!=0){
    var mdef=document.getElementById("m_"+def);
    mdef.className="m_li_a";
  }
  //子菜单
  var ss=document.getElementById("s_"+object);
  ss.style.display="none";
  //初始子菜单还原效果
  if(def!=0){
    var sdef=document.getElementById("s_"+def);
    sdef.style.display="block";
  }
}
</script>
</head>
<body>
<div id="menu">
  <ul>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_1" class='m_li_a'><a href="#">财税首页</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_2" class='m_li' onmouseover='mover(2);' onmouseout='mout(2);'><a href="#">政务公开</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_3" class='m_li' onmouseover='mover(3);' onmouseout='mout(3);'><a href="#">网上办事</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_4" class='m_li' onmouseover='mover(4);' onmouseout='mout(4);'><a href="#">公告中心</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_5" class='m_li' onmouseover='mover(5);' onmouseout='mout(5);'><a href="#">法规中心</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_6" class='m_li' onmouseover='mover(6);' onmouseout='mout(6);'><a href="#">财税文化</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_7" class='m_li' onmouseover='mover(7);' onmouseout='mout(7);'><a href="#">专题宣传</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
  </ul>
</div>
<div style="height:32px; background-color:#F1F1F1;">
   <ul class="smenu">
     <li style="padding-left:29px;" id="s_1" class='s_li_a'>欢迎光临乐清财税网，您是本站第2842位客人！</li>
     <li style="padding-left:141px;" id="s_2" class='s_li' onmouseover='mover(2);' onmouseout='mout(2);'><a href="#">财税简介</a>  |  <a href="#">机构设置</a>  |  <a href="#">办事指南</a>  |  <a href="#">税种简介</a>  |  <a href="#">财税动态</a>  |  <a href="#">公车动态</a></li>
     <li style="padding-left:252px;" id="s_3" class='s_li' onmouseover='mover(3);' onmouseout='mout(3);'><a href="#">下载专区</a>  |  <a href="#">上传专区</a>  |  <a href="j#">申请报名</a>  |  <a href="#">查询系统</a>  |  <a href="#">咨询投诉</a>  |  <a href="#">满意调查</a></li>
     <li style="padding-left:362px;" id="s_4" class='s_li' onmouseover='mover(4);' onmouseout='mout(4);'><a href="#">最新公告</a>  |  <a href="#">会计通知</a></li>
     <li style="padding-left:474px;" id="s_5" class='s_li' onmouseover='mover(5);' onmouseout='mout(5);'><a href="#">最新政策</a>  |  <a href="#">政策法规查询</a></li>
     <li style="padding-left:447px;" id="s_6" class='s_li' onmouseover='mover(6);' onmouseout='mout(6);'><a href="#">税收宣传</a>  |  <a href="#">队伍建设</a>  |  <a href="#">文明创建</a>  |  <a href="#" target="_blank">青年论坛</a>  |  <a href="#">廉政课堂</a></li>
     <li style="padding-left:696px;" id="s_7" class='s_li' onmouseover='mover(7);' onmouseout='mout(7);'><a href="#">专题宣传区</a></li>
   </ul>
</div>
</body>
</html>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<meta name="keywords" content="JS代码,菜单导航,JS广告代码,JS特效代码" />
<meta name="description" content="此代码内容为可跳转回首页的CSS二级联动菜单，属于站长常用代码，更多菜单导航代码请访问懒人图库JS代码频道。" />
<title>可跳转回首页的CSS二级联动菜单_懒人图库</title>
<link href="css/css.css" rel="stylesheet" type="text/css" />
<script>
//初始化
var def="1";
function mover(object){
  //主菜单
  var mm=document.getElementById("m_"+object);
  mm.className="m_li_a";
  //初始主菜单先隐藏效果
  if(def!=0){
    var mdef=document.getElementById("m_"+def);
    mdef.className="m_li";
  }
  //子菜单
  var ss=document.getElementById("s_"+object);
  ss.style.display="block";
  var temp ;
for(var k = 1 ; k <= 7 ; k ++){
if(k != object){
temp = document.getElementById("s_"+k);
temp.style.display = "none";
}
}
}function mout(object){
  //主菜单
  var mm=document.getElementById("m_"+object);
  mm.className="m_li";
  //初始主菜单还原效果
  if(def!=0){
    var mdef=document.getElementById("m_"+def);
    mdef.className="m_li_a";
  }
  //子菜单
  var ss=document.getElementById("s_"+object);
  ss.style.display="none";
  //初始子菜单还原效果
  if(def!=0){
    var sdef=document.getElementById("s_"+def);
    sdef.style.display="block";
  }
}function fn(object){
var mm=document.getElementById("m_"+object);
mm.style.display = "";
mm.onmouseout=null;
var ss;
for(var k = 1 ; k <= 7 ; k ++){
if(k != object){
ss = document.getElementById("s_"+k);
ss.style.display = "none";
}
}
}</script>
</head>
<body >
<div id="menu">
  <ul>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_1" class='m_li_a'><a href="#">财税首页</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_2" class='m_li' onmouseover='mover(2);' onmouseout='mout(2);' onclick="fn(2)"><a href="#">政务公开</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_3" class='m_li' onmouseover='mover(3);' onmouseout='mout(3);' onclick="fn(3)"><a href="#">网上办事</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_4" class='m_li' onmouseover='mover(4);' onmouseout='mout(4);' onclick="fn(4)"><a href="#">公告中心</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_5" class='m_li' onmouseover='mover(5);' onmouseout='mout(5);' onclick="fn(5)"><a href="#">法规中心</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_6" class='m_li' onmouseover='mover(6);' onmouseout='mout(6);' onclick="fn(6)"><a href="#">财税文化</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
    <li id="m_7" class='m_li' onmouseover='mover(7);' onmouseout='mout(7);' onclick="fn(7)"><a href="#">专题宣传</a></li>
    <li class="m_line"><img src="images/line1.gif" /></li>
  </ul>
</div>
<div style="height:32px; background-color:#F1F1F1;">
   <ul class="smenu">
     <li style="padding-left:29px;" id="s_1" class='s_li_a'>欢迎光临乐清财税网，您是本站第2842位客人！</li>
     <li style="padding-left:141px; display:none" id="s_2" class='s_li' onmouseover='mover(2);' onmouseout='mout(2);'><a href="#">财税简介</a>  |  <a href="#">机构设置</a>  |  <a href="#">办事指南</a>  |  <a href="#">税种简介</a>  |  <a href="#">财税动态</a>  |  <a href="#">公车动态</a></li>
     <li style="padding-left:252px; display:none" id="s_3" class='s_li' onmouseover='mover(3);' onmouseout='mout(3);'><a href="#">下载专区</a>  |  <a href="#">上传专区</a>  |  <a href="j#">申请报名</a>  |  <a href="#">查询系统</a>  |  <a href="#">咨询投诉</a>  |  <a href="#">满意调查</a></li>
     <li style="padding-left:362px; display:none" id="s_4" class='s_li' onmouseover='mover(4);' onmouseout='mout(4);'><a href="#">最新公告</a>  |  <a href="#">会计通知</a></li>
     <li style="padding-left:474px; display:none" id="s_5" class='s_li' onmouseover='mover(5);' onmouseout='mout(5);'><a href="#">最新政策</a>  |  <a href="#">政策法规查询</a></li>
     <li style="padding-left:447px; display:none" id="s_6" class='s_li' onmouseover='mover(6);' onmouseout='mout(6);'><a href="#">税收宣传</a>  |  <a href="#">队伍建设</a>  |  <a href="#">文明创建</a>  |  <a href="#" target="_blank">青年论坛</a>  |  <a href="#">廉政课堂</a></li>
     <li style="padding-left:696px; display:none" id="s_7" class='s_li' onmouseover='mover(7);' onmouseout='mout(7);' ><a href="#">专题宣传区</a></li>
   </ul>
</div>
</body>
</html>
http://www.lanrentuku.com/down/js/daohang-538，ie下和chrome、firefox下都对。恭喜。