1、引用jq和cookie，通过cookie判断是否首次打开。
2、定义弹出层代码<div class=”advbox”><div class=”advpic”><img width=”670″ height=”420″ alt=”” src=”images/xin.jpg”/><a href=”javascript:void(0);” class=”closebtn”>关闭</a></div></div>加入光比代码；
3、添加css样式*{margin:0;padding:0;list-style-type:none;}a,img{border:0;text-decoration:none;}body{font:12px/180% Arial, Helvetica, sans-serif,””;}/* advbox */*html,*html body{background-image:url(about:blank);background-attachment:fixed;}*html .advbox{position:absolute;top:expression(eval(document.documentElement.scrollTop));}.advbox{width:670px;position:fixed;display:none;left:50%;top:0;margin:-215px 0 0 -325px;}.advbox .advpic{position:relative;height:420px;overflow:hidden;}.advbox .advpic .closebtn{display:block;width:40px;height:20px;line-height:20px;font-size:12px;color:#fff;text-indent:12px;overflow:hidden;position:absolute;right:5px;top:0px;z-index:99;}
