1 <!DOCTYPE html>
2 <html>
3 <head>
4 <meta charset="utf-8">
5 <title></title>
6 <style>
7 #div1{width: 100px; height: 150px;background-color:red;position: absolute;
8 right:0;bottom: 0;}
9
10 </style>
11 <script>
12 window.onload=window.onscroll=function(){
13 var oDiv=document.getElementById('div1');
14 var scrollTop=document.documentElement.scrollTop||document.body.scrollTop;
15
16 // oDiv.style.top=(document.documentElement.clientHeight-oDiv.offsetLeft+scrollTop)/2+'px';
17
18 startMove(parseInt((document.documentElement.clientHeight-oDiv.offsetHeight)/2+scrollTop));
19 }
20
21 var timer=null;
22 function startMove(iTarget){
23 var oDiv=document.getElementById('div1');
24
25 clearInterval(timer);
26 timer=setInterval(function(){
27 var speed=(iTarget-oDiv.offsetTop)/4;
28 speed=speed>0?Math.ceil(speed):Math.floor(speed);
29 if(oDiv.offsetTop==iTarget){
30 clearInterval(timer);
31 }
32 else{
33 document.title=oDiv.offsetTop;
34 document.getElementById('txt1').value=oDiv.offsetTop;
35 oDiv.style.top=oDiv.offsetTop+speed+'px';
36 }
37 },30)
38 }
39 </script>
40 </head>
41 <body style="height: 2000px;">
42 <input type="text" id="txt1" style="position: fixed;right: 0; top: 0;" />
43 <div id="div1">
44 </div>
45 </body>
46 </html>