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);
}