<script type="text/javascript">jQuery(document).ready(function($) { /*start*/$("nav.main_menu").append("<div class=avia-menu2></div>");$("#avia-menu li.menu-item-has-children").hover(function(){var btmHeight = $(this).children("ul.sub-menu").height()+10;if(btmHeight<250){btmHeight=250}$(".avia-menu2").css({"opacity":"1","height":btmHeight});},function(){$(".avia-menu2").css({"opacity":"0","height":"0px"});});/*end*/ }) </script>
原文：http://luckyyang.blog.51cto.com/4524113/1795721