js控制固定div和随屏滚动div兼容多浏览器和纯css控制（来自网络）

 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

 <html xmlns="http://www.w3.org/1999/xhtml">

 <head>

     <meta http-equiv="Content-Type" content="text/html; charset=gbk" />

     <title>右下角div固定</title>

     <style type="text/css">

         html, body

         {

             padding: 0;

             margin: 0;

         }

     </style>

 </head>

 <body>

     <div id="aa" style="width: 100px; height: 100px; background: #c0c0c0;">随平滚懂div</div>

     <div id="bb" style="width: 100px; height: 100px; background: #c0c0c0;">静止不动div</div>

     <div style="width: 100%; height: 1500px; background: #000"></div>

     <div style="width: 100%; height: 1500px; background: green"></div>

     <div style="width: 100%; height: 1500px; background: red"></div>

 </body>

 </html>

 <script type="text/javascript">

     function scrollx(p) {

         var d = document, dd = d.documentElement, db = d.body, w = window, o = d.getElementById(p.id), ie6 = /msie 6/i.test(navigator.userAgent), style, timer;

         if (o) {

             o.style.cssText += ";position:" + (p.f && !ie6 ? 'fixed' : 'absolute') + ";" + (p.l == undefined ? 'right:0;' : 'left:' + p.l + 'px;') + (p.t != undefined ? 'top:' + p.t + 'px' : 'bottom:0');

             if (p.f && ie6) {

                 o.style.cssText += ';left:expression(documentElement.scrollLeft + ' + (p.l == undefined ? dd.clientWidth - o.offsetWidth : p.l) + ' + "px");top:expression(documentElement.scrollTop +' + (p.t == undefined ? dd.clientHeight - o.offsetHeight : p.t) + '+ "px" );';

                 dd.style.cssText += ';background-image: url(about:blank);background-attachment:fixed;';

             } else {

                 if (!p.f) {

                     w.onresize = w.onscroll = function () {

                         clearInterval(timer);

                         timer = setInterval(function () {

                             //双选择为了修复chrome 下xhtml解析时dd.scrollTop为 0

                             var st = (dd.scrollTop || db.scrollTop), c;

                             c = st - o.offsetTop + (p.t != undefined ? p.t : (w.innerHeight || dd.clientHeight) - o.offsetHeight);

                             if (c != 0) {

                                 o.style.top = o.offsetTop + Math.ceil(Math.abs(c) / 10) * (c < 0 ? -1 : 1) + 'px';

                             } else {

                                 clearInterval(timer);

                             }

                         }, 10)

                     }

                 }

             }

         }

     }

     scrollx({

         id: 'aa'

     })

     scrollx({

         id: 'bb',

         l: 0,

         t: 200,

         f: 1

     })

     /*

     id 你要滚动的内容的id

     l 横坐标的位置 不写为紧贴右边

     t 你要放在页面的那个位置默认是贴着底边 0是贴着顶边

     f 1表示固定 不写或者0表示滚动

     */

 </script>

本文来自：http://www.jzxue.com/wangyesheji/wangyetexiao/201011/09-4940.html

方式二：纯css控制且半透明效果，但兼容性较差

 #div_digg{ position:fixed; _position:absolute;z-index:;bottom:; right:; _right:17px; background-color:#FFFFFF;border:2px solid red;filter:alpha(Opacity=80);-moz-opacity:0.5;opacity: 0.5; }