当然，也有这方面很炫的代码，但是才跨浏览器方面功夫还是不够，呵呵。我遇到一个不错的css，在ie和firefox下浏览一样的效果。

      下图是实际运行的效果：

实际的效果大家可以参考：校园招聘一网打尽 http://www.xyzp.net/index.html

代码如下：

/*************************************************************************

  dw_viewport.js
  version date nov 2003
 
  this code is from dynamic web coding
  at http://www.dyn-web.com/
  copyright 2003 by sharon paine
  see terms of use at http://www.dyn-web.com/bus/terms.html
  regarding conditions under which you may use this code.
  this notice must be retained in the code as is!

*************************************************************************/ 
 
var viewport = {
  getwinwidth: function () {
    this.width = 0;
    if (window.innerwidth) this.width = window.innerwidth - 18;
    else if (document.documentelement && document.documentelement.clientwidth)
    this.width = document.documentelement.clientwidth;
    else if (document.body && document.body.clientwidth)
    this.width = document.body.clientwidth;
  },
 
  getwinheight: function () {
    this.height = 0;
    if (window.innerheight) this.height = window.innerheight - 18;
   else if (document.documentelement && document.documentelement.clientheight)
    this.height = document.documentelement.clientheight;
   else if (document.body && document.body.clientheight)
    this.height = document.body.clientheight;
  },
 
  getscrollx: function () {
    this.scrollx = 0;
   if (typeof window.pagexoffset == "number") this.scrollx = window.pagexoffset;
   else if (document.documentelement && document.documentelement.scrollleft)
    this.scrollx = document.documentelement.scrollleft;
   else if (document.body && document.body.scrollleft)
    this.scrollx = document.body.scrollleft;
   else if (window.scrollx) this.scrollx = window.scrollx;
  },
 
  getscrolly: function () {
    this.scrolly = 0;   
    if (typeof window.pageyoffset == "number") this.scrolly = window.pageyoffset;
    else if (document.documentelement && document.documentelement.scrolltop)
    this.scrolly = document.documentelement.scrolltop;
   else if (document.body && document.body.scrolltop)
    this.scrolly = document.body.scrolltop;
   else if (window.scrolly) this.scrolly = window.scrolly;
  },
 
  getall: function () {
    this.getwinwidth(); this.getwinheight();
    this.getscrollx();  this.getscrolly();
  }
 
}

/*************************************************************************
    dw_event.js (version date feb 2004)
       
    this code is from dynamic web coding at http://www.dyn-web.com/
    see terms of use at http://www.dyn-web.com/bus/terms.html
    regarding conditions under which you may use this code.
    this notice must be retained in the code as is!
*************************************************************************/

var dw_event = {
 
  add: function(obj, etype, fp, cap) {
    cap = cap || false;
    if (obj.addeventlistener) obj.addeventlistener(etype, fp, cap);
    else if (obj.attachevent) obj.attachevent("on" + etype, fp);
  },

  remove: function(obj, etype, fp, cap) {
    cap = cap || false;
    if (obj.removeeventlistener) obj.removeeventlistener(etype, fp, cap);
    else if (obj.detachevent) obj.detachevent("on" + etype, fp);
  },

  domit: function(e) {
    e = e? e: window.event;
    e.tgt = e.srcelement? e.srcelement: e.target;
   
    if (!e.preventdefault) e.preventdefault = function () { return false; }
    if (!e.stoppropagation) e.stoppropagation = function ()
{ if (window.event) window.event.cancelbubble = true; }
       
    return e;
  }
 
}
/*************************************************************************
  dw_tooltip.js   requires: dw_event.js and dw_viewport.js
  version date: march 14, 2005
  (minor changes in position algorithm and timer mechanism)
 
  this code is from dynamic web coding at dyn-web.com
  copyright 2003-5 by sharon paine
  see terms of use at www.dyn-web.com/bus/terms.html
  regarding conditions under which you may use this code.
  this notice must be retained in the code as is!
*************************************************************************/