好的，谢谢。
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<style type="text/css">
<!--
#tab1 ,#tab2{width:435px;border:1px #cfedff solid;border-bottom:0; background-color:#FFFFFF; padding-left:0px;}
#tab1 ul ,#tab2 ul{margin:0;padding:0;}
#tab1 li,#tab2 li{float:left; height:22px;line-height:22px;text-align:center; border-left:1px solid #C0C2DF; padding:none; border-bottom:1px solid #C0C2DF; cursor:default;}
#tab1 li img{vertical-align:middle; border:none; padding:none;}
#tab1 li.now,#tab2 li.now{color:#5299c4;background:#fff;}
.tablist{width:435px; padding-left:1px;font-size:14px;line-height:18px;border:1px #cfedff solid;border-top:0;display:none;}
.block{display:block;}
-->
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</head>
<script type="text/javascript">
//m选项卡数目
//n当前选项卡编号
function setTab(m,n){
var menu=document.getElementById("tab"+m).getElementsByTagName("li");
//获取ID为tab+m标签下的li标签
var showdiv=document.getElementById("tablist"+m).getElementsByTagName("div");
//获取ID为tablist+m标签下的div标签
for(i=0;i<menu.length-1;i++)
{
menu[i].className=i==n?"now":"";
//如果i=n;那么menu[i].classname为now
showdiv[i].style.display=i==n?"block":"none";
//如果如果i=n;那么showdiv[i].style.display为block"
}
}
</script>
<body>
<div id="tab1">
<ul>
<li onmouseover="setTab(1,0)" class="now" style="background-color:#FFFFFF; width:105px;">第一页</li>
<li onmouseover="setTab(1,0)" class="now" style="background-color:#FFFFFF; width:105px;">第二页</li>
<li onmouseover="setTab(1,0)" class="now" style="background-color:#FFFFFF; width:105px;">第三页</li>
<li onmouseover="setTab(1,0)" class="now" style="background-color:#FFFFFF; width:105px;">第四页</a></li>
</ul>
</div>
<div id="tablist1">
<div class="tablist block" style="background-color:#FFFFFF;">
<iframe border="0" frameborder="no" marginwidth="0" marginheight="0" scrolling="no" hspace="0" vspace="0" src="1"></iframe>
</div>
<div class="tablist" style="background-color:#FFFFFF;">
<iframe border="0" frameborder="no" marginwidth="0" marginheight="0" scrolling="no" hspace="0" vspace="0" src="2"></iframe>
</div>
<div class="tablist" style="background-color:#FFFFFF;">
<iframe border="0" frameborder="no" marginwidth="0" marginheight="0" scrolling="no" hspace="0" vspace="0" src="3"></iframe>
</div>
<div class="tablist" style="background-color:#FFFFFF;">
<iframe border="0" frameborder="no" marginwidth="0" marginheight="0" scrolling="no" hspace="0" vspace="0" src="4"></iframe>
</div>
</div>
</div>
</body>
</html>
