让IE6下支持固定定位

让IE下支持固定定位

 1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
 2 <html xmlns="http://www.w3.org/1999/xhtml">
 3 <head>
 4 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
 5 <title>无标题文档</title>
 6 <style>
 7 body {
 8     _background-image: url(null); /*空背景*/
 9     /*_background-image: url(about:blank);*/
10     _background-attachment: fixed; /* 固定背景 */
11 }
12 
13 #fixed {
14     position: fixed;
15     top: 50%; /* 非IE下的定位 */
16     _position: absolute; /*IE6 用absolute模拟fixed*/
17     _top: expression(document.documentElement.scrollTop +   Math.round (
18         document.documentElement.offsetHeight/ 2)+  "px"); /*IE6 动态top值*/
19     right: 0;
20     width: 30px;
21     height: 100px;
22     margin-top: -50px;
23     background: #F30;
24 }
25 </style>
26 </head>
27 <body style="height: 3000px;">
28     <div id="fixed"></div>
29 </body>
30 </html>

 1 <style>
 2 .box{height:2000px;}
 3 .div{width:100px;height:100px;background:red; position:fixed;left:100px;top:100px; _position:absolute;_top:expression(eval(document.documentElement.scrollTop+100));
 4 }
 5 </style>
 6 </head>
 7 <body>
 8 <div class="box">
 9     <div class="div"></div>
10 </div>