<script src="http://cdn.bootcss.com/jquery/1.11.1/jquery.min.js"></script><script type="text/javascript">$(function(){ ???var TIMER;//定义全局变量 ???$(window).scroll( function() { ???????clearTimeout(TIMER);//必须要有这句 ???????if( $(document).scrollTop() > 0 ){ ???????????TIMER = setTimeout(function(){ ???????????????$("#aaa").addClass("abc");console.log($(document).scrollTop()); ???????????},100); ???????}else{ ???????????TIMER = setTimeout(function(){ ???????????????$("#aaa").removeClass("abc"); ???????????},100); ???????} ???});});</script><style type="text/css">html,body{margin:0;padding:0;}#aaa{width:100%;height:40px;line-height:40px;background:#3399cc;}.abc{position:fixed;left:0;right:0;top:0;}</style><div id="aaa">aaaaaaa</div>js实现div吸顶效果
原文地址：http://www.cnblogs.com/dongruiha/p/7692221.html