JavaScript 最短的拖动代码[兼容FF]

<!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=gb2312" />    <body>  <div id="test" style="background-color:#0099CC;width:200px"onmouseover='Move_obj("test")'>这个是可以拖动的层</div> 

[Ctrl+A 全选 注:引入外部Js需再刷新一下页面才能执行]