超简单实用的Jquery下拉菜单
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
var objStr = "#UpLayer";
$(objStr).mouseover(function(){$(objStr + " ul").show();});
$(objStr).mouseout(function(){$(objStr + " ul").hide();});
});
</script>
<div id="UpLayer">
<span><a href="javascript:void(0)">jquery</a></span>
<ul>
<li><a href="http://bunsen.cn/" target="_blank">bunsen博客</a></li>
<li><a href="http://bunsen.cn/" target="_blank">bunsen特效</a></li>
<li><a href="http://bunsen.cn/" target="_blank">jquery_bunsen</a></li>
<li><a href="http://bunsen.cn/" target="_blank">前端开发</a></li>
</ul>
</div>