<!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>无标题文档</title>
<style type="text/css">
a{ color:#c00; text-decoration:none;}
a:hover{ color:#00f;}
ul{ list-style:none; padding:0; margin:0px; text-align:center;}
#tab{ width:460px; margin:0 auto; font-size:12px;}
.menubox{ width:100%; background:url(../../img图片/CD0026.jpg); height:28px; line-height:28px;}
.menubox ul{ margin:0px; padding:0px;}
.menubox li{ float:left; display:block; cursor:pointer; width:114px; text-align:center; color:#949694; font-weight:bold;}
.menubox li.hover{ padding:0px; background:#fff; width:116px;border-bottm:none; background:url(../../img图片/CNDESK_34gjr060708202647.jpg); color:#739242; height:27px; line-height:27px;}
.contentbox{ clear:both; margin-top:0px; border:1px solid #a8c29f; border-top:none; height:181px; padding-top:8px;}
.hide{ display:none;}
<script>
var i;
var n;
var set;
function settab(n){
for(i=1;i<=n;i++){
var menu=document.getelementbyid("tab_"+i);
var con=document.getelementbyid("con_"+i);
menu.classname=i==cursel?"hover":"";
con.style.display=i==cursel?"block":"none";
}
}
</script>
</style>
</head>
<body>
<div id="tab">
<div class="menubox">
<ul>
<li id="tab_1" class="hover" onclick="settab(1);">tab菜单1</li>
<li id="tab_2" onclick="settab(2);">tab菜单2</li>
<li id="tab_3" onclick="settab(3);">tab菜单3</li>
<li id="tab_4" onclick="settab(4);">tab菜单4</li>
</ul>
</div>
<div class="contentbox">
<div id="con_1" class="hover">Tab包含框1</div>
<div id="con_2" class="hide">Tab包含框2</div>
<div id="con_3" class="hide">Tab包含框3</div>
<div id="con_4" class="hide">Tab包含框4</div>
</div>
</div>
</body>
</html>
其中jeff函数怎么错了！