网页两侧随滚动条上下移动的图片代码

var left_img='<a target=_blank href="http://www.i263.net"><img src=one.gif border=0></a>';
var right_img='<a target=_blank href="http://www.i263.net"><img src=two.gif border=0></a>';

var delta=0.05
var collection;
function floaters() {
this.items = [];
this.addItem = function(id,x,y,content)
{
document.write('<DIV id='+id+' style="Z-INDEX: 10; 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;
new