帮我解释一下下边的JavaScript代码：

Question

以为我是在发广告吧？代码：
///---最简单的js对联广告代码----- 
function close163news(){ 
searchspe.style.visibility='hidden';searchspe2.style.visibility='hidden'; 
} 
var specialcode="<DIV id=searchspe style='Z-INDEX: 100; right: -10px; POSITION: absolute; TOP: 30px;'><table ><tr><td><img src='http://www.haodd123.com/close.gif' onclick='close163news()'/></td></tr><tr><td><iframe src='http://www.haodd123.com/adcode.asp' frameborder='0' scrolling='no' width='120' height='600'></iframe> </td></tr></table></DIV>"; 
document.write(specialcode); 
lastScrollX=0; 
function heartBeat0(){ 
diffY=document.body.scrollTop; 
percent=.1*(diffY-lastScrollX); 
if(percent>0) 
percent=Math.ceil(percent); 
else percent=Math.floor(percent); 
document.all.searchspe.style.pixelTop+=percent; 
lastScrollX=lastScrollX+percent; 
} 
window.setInterval("heartBeat0()",1); 
var specialcode2="<DIV id=searchspe2 style='Z-INDEX: 100; left: -10px; POSITION: absolute; TOP: 30px;'><table ><tr><td><img src='http://www.haodd123.com/close.gif' onclick='close163news()'/></td></tr><tr><td><iframe src='http://www.haodd123.com/adcode.asp' frameborder='0' scrolling='no' width='120' height='600'></iframe> </td></tr></table></DIV>"; 
document.write(specialcode2); 
lastScrollY=0; 
function heartBeat1(){ 
diffY=document.body.scrollTop; 
percent=.1*(diffY-lastScrollY); 
if(percent>0)percent=Math.ceil(percent); 
else percent=Math.floor(percent); 
document.all.searchspe2.style.pixelTop+=percent; 
lastScrollY=lastScrollY+percent; 
} 
window.setInterval("heartBeat1()",1); 
-->