JavaScript页面跟随滚动条两侧漂浮广告

var showad = true;
var theTop = 60; // 上端位置
var AdDivW = 100; // 宽度
var AdDivH = 300; // 高度
var PageWidth = 800; // 页面多少宽度象素下正好不出现左右滚动条
var MinScreenW = 1024; // 显示广告的最小屏幕宽度象素
var old = theTop;
var tipLeft;
var tipRight;
var AdContentHtmlLeftUrl = "http://fbzl.org/"; // 左侧广告Url
var AdContentHtmlLeftImage = "https://blog.fbzl.org/wp-content/uploads/2013/05/IMG_1794.png"; //左侧广告Image
var AdContentHtmlRightUrl = "http://fbzl.org/"; // 右侧广告Url
var AdContentHtmlRightImage = "https://blog.fbzl.org/wp-content/uploads/2013/05/IMG_1794.png"; //右侧广告Image
var ClosebuttonHtml = '<div style="position: absolute; top: 0px; right: 0px; margin: 2px; padding: 2px; z-index: 2000;" align="right"><a style="color: red; text-decoration: none; font-size: 12px;">关闭</a>';
document.write('<div id="JavascriptLeftDiv" style="position: absolute; border: 1px solid #336699; background-color: #eeeee2; z-index: 1000; width: ' + AdDivW + 'px; height: ' + AdDivH + 'px; top: ' + theTop + 'px; word-break: break-all;">' + ClosebuttonHtml + '<div> <div style="color: green; font-size: 23pt; font-family: 黑体;" align="center"><a href="' + AdContentHtmlLeftUrl + '" target="_blank"><img src="' + AdContentHtmlLeftImage + '" width="100" height="300" border="0" /></a></div> </div> </div> ');

document.write('<div id="JavascriptRightDiv" style="position: absolute; border: 1px solid #336699; background-color: #eeeee2; z-index: 1000; width: ' + AdDivW + 'px; height: ' + AdDivH + 'px; top: ' + theTop + 'px; word-break: break-all;">' + ClosebuttonHtml + '<div> <div style="color: green; font-size: 23pt; font-family: 黑体;" align="center"><a href="' + AdContentHtmlRightUrl + '" target="_blank"><img src="' + AdContentHtmlRightImage + '" width="100" height="300" border="0" /></a></div> </div> </div> ');

function initFloatTips() {
    tipLeft = document.getElementById('JavascriptLeftDiv');
    tipRight = document.getElementById('JavascriptRightDiv');
    scall();
};

function scall() {
    var grantt = 20;
    if (!showad) {
        return;
    }
    if (window.screen.width < MinScreenW) {
        alert("临时提示：\n\n显示器分辨率宽度小于" + MinScreenW + ",不显示广告");
        showad = false;
        document.getElementById("Javascript.LeftDiv").style.display = "none";
        document.getElementById("Javascript.RightDiv").style.display = "none";
        return;
    }
    if (window.innerHeight) {
        pos = window.pageYOffset
    } else if (document.documentElement && document.documentElement.scrollTop) {
        pos = document.documentElement.scrollTop
    } else if (document.body) {
        pos = document.body.scrollTop;
    }
    pos = pos - tipLeft.offsetTop + theTop;
    pos = tipLeft.offsetTop + pos / 10;
    if (pos < theTop) pos = theTop;
    if (pos != old) {
        tipLeft.style.top = pos + "px";
        tipRight.style.top = pos + "px";
        grantt = 10;
    }
    old = pos;
    setTimeout(scall, grantt);
}

function hidead() {
    showad = false;
    document.getElementById("JavascriptLeftDiv").style.display = "none";
    document.getElementById("JavascriptRightDiv").style.display = "none";
}

initFloatTips();