上下跳动的宣传图片

看到效果显示了吧！

脚本说明:
把如下代码加入<body>区域中
<script language="javascript">
var brOK=false;
var mie=false;
var aver=parseInt(navigator.appVersion.substring(0,1));
var aname=navigator.appName;
var mystop=0;
var step=0.2;
function checkbrOK()
{if(aname.indexOf("Internet Explorer")!=-1)
{if(aver>=4) brOK=navigator.javaEnabled();
mie=true;
}
if(aname.indexOf("Netscape")!=-1)  
{if(aver>=4) brOK=navigator.javaEnabled();}
}
var vmin=1.5;
var vmax=3;
var vr=2;
var timer1;
function Chip(chipname,width,height)
{this.named=chipname;
this.vx=vmin+vmin;
this.vy=0;
this.w=width;
this.h=height;
this.xx=0;
this.yy=0;
this.timer1=null;
}
function movechip(chipname)
{
if(brOK && mystop==0)
{eval("chip="+chipname);
if(!mie)
{pageX=window.pageXOffset;
pageW=window.innerWidth;
pageY=window.pageYOffset;
pageH=window.innerHeight;
}
else
{
pageX=window.document.body.scrollLeft;
pageW=window.document.body.offsetWidth-8;
pageY=window.document.body.scrollTop;
pageH=window.document.body.offsetHeight-4;
} 
chip.xx=chip.xx+chip.vx;
chip.vy=chip.vy+step;
chip.yy=chip.yy+chip.vy;
if(chip.xx<=pageX)
{chip.xx=pageX;
chip.vx=vmin;
}
if(chip.xx>=pageX+pageW-85)
{
chip.xx=pageX;
chip.vx=vmin;
chip.yy=pageY;
chip.vy=vmin+vmax;
}

if(chip.yy>(pageY+pageH-chip.h))
{
chip.yy=pageY+pageH-chip.h;
chip.vy=-chip.vy*0.65;
}

if(!mie)
{eval('document.'+chip.named+'.top ='+chip.yy);
eval('document.'+chip.named+'.left='+chip.xx);
} 
else
{eval('document.all.'+chip.named+'.style.pixelLeft='+chip.xx);
eval('document.all.'+chip.named+'.style.pixelTop ='+chip.yy); 
}
	chip.timer1=setTimeout("movechip('"+chip.named+"')",40);
}
}

function stopme(flag)
{
brOk=true;
mystop=flag;
movechip("tome");
}

var tome;
var chip;
function tome()
{checkbrOK(); 
tome=new Chip("tome",80,80);
if(brOK && mystop==0) 
{ 
movechip("tome");
}
}

ns4=(document.layers)?true:false;
ie4=(document.all)?true:false;