椰棕床垫的好处:请问网页上漂浮对联的漂浮速度是怎么设置，参数是哪个，谢谢。

代码如下：
var delta=0.015
var collection;
function floaters() {
this.items = [];
this.addItem = function(id,x,y,content)
{
document.write('<DIV id='+id+' style="Z-INDEX: 0; POSITION: absolute; width:80px; height:60px;left:'+(typeof(x)=='string'?eval(x):x)+';top:'+(typeof(y)=='string'?eval(y):y)+'">'+content+'</DIV>');

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()
{
if(screen.width<=800)
{
for(var i=0;i<collection.length;i++)
{
collection[i].object.style.display = 'none';
}
return;
}
for(var i=0;i<collection.length;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.body.scrollTop+followObj_y)) {
var dy=(document.body.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-100',0,'</a><br><a href=http://www.941mm.com/dy/dy.htm target=_blank><img src=http://www.941mm.com/dy/images/dy04.gif width=100 height=250 border=0></a>');
theFloaters.addItem('followDiv2',0,0,'<br><a href=http://www.941mm.com/dy/dy.htm target=_blank><img src=http://www.941mm.com/dy/images/dy03.gif width=100 height=250 border=0></a>');
theFloaters.play();