三院304所待遇:对联代码

我网上找了段代码,已经在望站上运行了,如何在这段代码上加关闭的按钮..谢谢了!!!

代码如下:

function initEcAd() {
document.all.AdLayer1.style.posTop =200;
document.all.AdLayer1.style.visibility = 'visible'
document.all.AdLayer2.style.posTop =200;
document.all.AdLayer2.style.visibility = 'visible'
MoveLeftLayer('AdLayer1');
MoveRightLayer('AdLayer2');
}
function MoveLeftLayer(layerName) {
var x = 16;
var y = 130;
var diff = (document.body.scrollTop + y - document.all.AdLayer1.style.posTop)*.40;
var y = document.body.scrollTop + y - diff;
eval("document.all." + layerName + ".style.posTop = y");
eval("document.all." + layerName + ".style.posLeft = x");
setTimeout("MoveLeftLayer('AdLayer1');", 20);
}
function MoveRightLayer(layerName) {
var x = 16;
var y = 130;
var diff = (document.body.scrollTop + y - document.all.AdLayer2.style.posTop)*.40;
var y = document.body.scrollTop + y - diff;
eval("document.all." + layerName + ".style.posTop = y");
eval("document.all." + layerName + ".style.posRight = x");
setTimeout("MoveRightLayer('AdLayer2');", 20);
}
document.write("<div id=AdLayer1 style='position: absolute;visibility:hidden;z-index:1'><a href=# target=_blank ><img src=图 border=0></a></div>"
+"<div id=AdLayer2 style='position: absolute;visibility:hidden;z-index:1'><a href=# target=_blank ><img src=图 border=0></a></div>");
initEcAd()