1 <!DOCTYPE HTML>
 2 <html>
 3 <head>
 4 <meta charset="utf-8">
 5 <script language="javascript" src="js/jquery-1.7.2.min.js"  type="text/javascript"></script>
 6 
 7 <style type="text/css">
 8 body{
 9     text-align:center;
10 
11 
12 }
13     #back_to_top{
14         display: none;
15     position:fixed;
16     _position:absolute;
17     z-index:100;
18     background: url(data:image/png;base64,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) no-repeat left top;
19     width: 59px !important;
20     height: 59px !important;
21     right:0;
22     bottom:0;
23     _top:expression(eval(document.documentElement.scrollTop+document.documentElement.clientHeight-this.offsetHeight-(parseInt(this.currentStyle.marginTop,10)||0)-(parseInt(this.currentStyle.marginBottom,10)||0)));
24     }
25     
26 </style>
27 <script language="javascript" type="text/javascript">
28     $(function(){
29     $(window).scroll(function() {
30         if ($(window).scrollTop()>0){
31             $("#back_to_top").fadeIn(500);
32         }
33         else{
34             $("#back_to_top").fadeOut(500);
35         }
36         back_to_top();
37     });
38         $("#back_to_top").click(function(){
39             $('body,html').animate({scrollTop:0},300);
40             return false;
41         });
42     });
43 </script>
44 </head>
45 
46 <body>
47     <br >
48     顶部
49     <hr/>
50     <div id="back_to_top"></div>
51     <br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br >
52      <br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br ><br >
53      <hr />
54     底站
55 </body>
56 </html>