返回顶部

<!DOCTYPE html>
<meta charset="utf-8">

<title>tab选项卡学习</title>
<style>
html,body,ul,li{padding:0;margin:0}
ul{list-style-type:none}
clear{ clear:both;}
.box{ 960px; height:2000px; margin:0 auto; background:#999;}
span{ position:fixed; _position:absolute; top:0; left:0; 20px; border:1px solid #666; display:none;}
</style>
<div class="box"></div>
<span>返回顶部</span>

<script src="jquery-1.8.3.min.js"></script>
<script>
$(window).scroll(function(){
   var ws=$(window).scrollTop(),
       wh=$(window).height(),
       nw=$(window).width(),
       lv=(nw-960)/2+970,
       xx=$('span').height()+120;
       //console.log(ws);
   if(ws){
       $('span').show().css({left:lv,top:wh-xx});
       if($.browser.msie&&($.browser.version === "6.0")){
               $('span').css("top",wh-xx+ws);
           }
   }else{
       $('span').hide();
   }


});
   $('span').click(function(){
       $(window).scrollTop(0);
   });

</script>