在使用以下声明时，会使一个最常用的漂浮下拉广告失效:

http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
http://www.w3.org/1999/xhtml">

直接导致document.body.scrollTop永远等于0，　body Scroll永远也不会引发。

搜索了一下，发现了解决方案:

document.documentElement.scrollTop　替代　document.body.scrollTop

以下是正确的漂浮广告下拉代码，在所谓的"W3C标准"里可以正确运行 :

var delta=0.15
var collection;
function floaters() {
this.items = [];
this.addItem = function(id,x,y,content)
{
document.write('' ''+content+'''');

var newItem = {};
newItem.object = document.getElementById(id);
newItem.x = x;
newItem.y = y;

this.items[this.items.length] = newItem;
}
this.play = function()
{
collection = this.items
setInterval(''play()'',10);
}
}
function play()
{

for(var i=0;i {
var followObj = collection[i].object;
var followObj_x = (typeof(collection[i].x)==''string''?eval(collection[i].x):collection[i].x);
var followObj_y = (typeof(collection[i].y)==''string''?eval(collection[i].y):collection[i].y);

if(followObj.offsetLeft!=(document.body.scrollLeft+followObj_x)) {
var dx=(document.body.scrollLeft+followObj_x-followObj.offsetLeft)*delta;
dx=(dx>0?1:-1)*Math.ceil(Math.abs(dx));
followObj.style.left=followObj.offsetLeft+dx;
}

if(followObj.offsetTop!=(document.documentElement.scrollTop+followObj_y)) {
var dy=(document.documentElement.scrollTop+followObj_y-followObj.offsetTop)*delta;
dy=(dy>0?1:-1)*Math.ceil(Math.abs(dy));
followObj.style.top=followObj.offsetTop+dy;
}
followObj.style.display = '''';
}
}

var theFloaters = new floaters();
theFloaters.addItem(''followDiv1'',''document.body.clientWidth-108'',1,''http://sms.tom.com/pkly/pkly.html" target="_blank" />http://smsad.tom.com/smsweb/images/2005_new/cn/qp_100x400.gif" width="100" height="400" />'');

theFloaters.play();