js 漂浮在右边的图片 图片会跟这滚动条走

var speed = 10
var currentpos = 0, alt = 1, curpos1 = 0, curpos2 = -1
function initialize() {
startit()
}
function scrollwindow() {
if (document.all)
temp = document.documentElement.scrollTop
else
temp = window.pageYOffset
if (alt == 0)
alt = 1
else
alt = 0
if (alt == 0)
curpos1 = temp
else
curpos2 = temp
if (curpos1 != curpos2) {
if (document.all)
currentpos = document.documentElement.scrollTop - speed
else
currentpos = window.pageYOffset - speed
window.scroll(0, currentpos)
} else {
currentpos = 0
window.scroll(0, currentpos)
}
if (document.documentElement.scrollTop < 5) {
window.clearInterval(intervalID);
}
}
function startit() {
intervalID = setInterval("scrollwindow()", 5)
}
lastScrollY = 0;
function heartBeat() {
var diffY;
if (document.documentElement && document.documentElement.scrollTop)
diffY = document.documentElement.scrollTop;
else if (document.body)
diffY = document.body.scrollTop
else {
}
percent = .1 * (diffY - lastScrollY);
if (percent > 0)
percent = Math.ceil(percent);
else
percent = Math.floor(percent);
document.getElementById("scrollfull").style.top = parseInt(document.getElementById("scrollfull").style.top) + percent + "px";

lastScrollY = lastScrollY + percent;
}

function combineFloatDiv(url){
suspendcode = '<div id="scrollfull" style="position:absolute;z-index:9999; right:0px; top:250px;">' +
'<a href="'+url+'"><img src="'+contextPath+'/images/bsxz.gif" /></a></div>';
$("#float_div").html(suspendcode);
window.setInterval("heartBeat()", 10);
}