function initAd(){ 
document.all.AdLayer.style.posTop = -200; 
document.all.AdLayer.style.visibility = 'visible'//设置广告层为可见 
MoveLayer('AdLayer'); 
} 

function MoveLayer(layerName){ 
var x = document.body.clientWidth-160;//浮动广告层固定于浏览器的x方向位置(浏览器宽度-图片宽度) 
var y = document.body.clientHeight-70;//浮动广告层固定于浏览器的y方向位置(浏览器高度-图片高度) 
var diff = (document.body.scrollTop + y - document.all.AdLayer.style.posTop)*.40; 
var y = document.body.scrollTop + y - diff; 
eval("document.all." + layerName + ".style.posTop = y"); //移动广告层 
eval("document.all." + layerName + ".style.posLeft = x");//移动广告层 
setTimeout("MoveLayer('AdLayer');", 10); 
}