<!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">
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<meta http-equiv="Content-Type" content="text/htmlcharset=gb2312" />
<title>无标题文档</title>
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color:#0066FF
line-height:39px
padding-left:15px
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width:280px
height:45px
border:2px #FF9900 solid
background-color:#FFF3E8
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font-weight:bold
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<script>
var num=12//确定li数量。
function a() //网页加载的时候设置li背景颜色。
{
var a=document.getElementById("uu").getElementsByTagName("li")
for(var i=0i<numi++)
{
if((i%2)==1) a[i].style.display="none"
if((i%4)==0) a[i].style.backgroundColor="#dddddd" //设置li的背景颜色。
}
}
function over(n)
{
var a=document.getElementById("uu").getElementsByTagName("li")
for(var i=0i<numi++) //一个循环让鼠标经过的li显示对应的装有详细内容的li。
{
if((i%2)==1) a[i].style.display="none"
else
a[i].style.display="block"
}
a[n].style.display="none"
a[n+1].style.display="block"
}
</script>
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<body onload="a()">
<div id="zhuti">
<ul id="uu">
<li class="h" onmouseover="over(0)">知性OL－简约大方通勤必备 </li>
<li class="xianshi">知性OL－简约大方通勤必备知性OL－简约大方通勤必备<br /><font color="#CC0000">淘宝价：xx</font></li>
<li class="h" onmouseover="over(2)">淑女系－可爱小女生最爱 </li>
<li class="xianshi">淑女系－可爱小女生最爱淑女系－可爱小女生最爱<br /><font color="#CC0000">淘宝价：xx</font></li>
<li class="h" onmouseover="over(4)">时尚派－柱形手提斜挎女包 </li>
<li class="xianshi">时尚派－柱形手提斜挎女包时尚派－柱形手提斜挎女包<br /><font color="#CC0000">淘宝价：xx</font></li>
<li class="h" onmouseover="over(6)">蝴蝶结－闪金淡蓝可爱单鞋 </li>
<li class="xianshi">蝴蝶结－闪金淡蓝可爱单鞋蝴蝶结－闪金淡蓝可爱单鞋<br /><font color="#CC0000">淘宝价：xx</font></li>
<li class="h" onmouseover="over(8)">坡跟鞋－韩版甜美坡跟凉鞋 </li>
<li class="xianshi">坡跟鞋－韩版甜美坡跟凉鞋坡跟鞋－韩版甜美坡跟凉鞋<br /><font color="#CC0000">淘宝价：xx</font></li>
<li class="h" onmouseover="over(10)">高跟鞋－复古小名媛圆头鞋 </li>
<li class="xianshi">高跟鞋－复古小名媛圆头鞋高跟鞋－复古小名媛圆头鞋<br /><font color="#CC0000">淘宝价：xx</font></li>
</ul>
</div>
</body>
</html>
不知道你是像继续添加内容还是继续添加导航标签，所以都加了。看了一下你这个代码还是很简单的，所以稍微改了点
<div id="right_new">
<script language=javascript>
function secBoard(n) {
var menu = document.getElementById('menu').getElementsByTagName('li')
var main1 = document.getElementById('main1').getElementsByTagName('div')
for (i = 0i <menu.lengthi++) {
menu[i].className = "sec1"
}
menu[n].className = "sec2"
for (i = 0i <main1.lengthi++) {
main1[i].style.display = "none"
}
main1[n].style.display = "block"}
</script>
<div id="header"><!--导航选项区域-->
<div id="right_menu">
<ul id="menu">
<li onMouseOver="secBoard(0)" class="sec2">最新推荐</li>
<li onMouseOver="secBoard(1)" class="sec1">热门排行</li>
<li onMouseOver="secBoard(2)" class="sec1">3333</li>
<li onMouseOver="secBoard(3)" class="sec1">4444</li>
</ul>
</div><!--导航选项区域-->
<!--内容显示区域-->
<div id="main1"><br>
<div class="block">
<li>最新推荐：<a href=" http://xu123.lingd.net/article-4287887-1.html"target="_blank">JS图片轮播幻灯片切换效果</a></li>
<li>最新推荐：<a href=" http://xu123.lingd.net/article-4287887-1.html"target="_blank">JS图片轮播幻灯片切换效果</a></li>
<li>最新推荐：<a href=" http://xu123.lingd.net/article-4287887-1.html"target="_blank">JS图片轮播幻灯片切换效果</a></li>
<li>最新推荐：<a href=" http://xu123.lingd.net/article-4287887-1.html"target="_blank">JS图片轮播幻灯片切换效果</a></li>
</div>
<div class="unblock">热门排行：<a href=" http://xu123.lingd.net/article-2712422-1.html"target="_blank">点击连接弹出层，背景变暗</a></div>
<div class="unblock">3333：<a href=" http://xu123.lingd.net/article-2712422-1.html"target="_blank">点击连接弹出层，背景变暗</a></div>
<div class="unblock">4444：<a href=" http://xu123.lingd.net/article-2712422-1.html"target="_blank">点击连接弹出层，背景变暗</a></div>
</div><!--内容显示区域-->
</div>
</div>
根据自己的需求改吧。
