<style>
*{ margin:0; padding:0; list-style:none;}
body{ font:normal 14px/24px 'MicroSoft YaHei';}
.cotrs{ 960px; height:32px; line-height:32px; background:#999; margin:0 auto;}
.cotrs a{ height:32px; line-height:32px; color:#fff; text-decoration:none; padding:0px 10px; display:block; float:left;}
.cotrs a:hover{ text-decoration:none; background:#000;}
.cotrs a.thisclass{text-decoration:none; background:#000;}
</style>
<body>
<div class="cotrs">
<a href='javascript:' class="thisclass">菜单一</a>
<a href='javascript:'>菜单二</a>
<a href='javascript:'>菜单三</a>
<a href='javascript:'>菜单四</a>
<a href='javascript:'>菜单五</a>
</div>
</body>
<script>
$(function(){
var cotrs = $(".cotrs a");
cotrs.click(function(){
$(this).addClass("thisclass").siblings().removeClass("thisclass");
});
});
</script>