动态随滚动条一起滚动DIV，点击恢复滚动条位置
给网页添加随滚动条一起滚动按钮，单击按钮滚动条恢复到网页顶部。(兼容ie6,ie7,ie8,firefox,chrome)var floatDiv;var visibleHeight ;var visibleWidth ;//初始化函数，判断是否要创建滚动DIVwindow.onload = function(){ visibleHeight = (document.documentElement.clientHeight == 0 ? document.body.clientHeight : document.documentElement.clientHeight); visibleWidth = (document.documentElement.clientWidth == 0 ? document.body.clientWidth : document.documentElement.clientWidth); var _scrollHeight = Math.max(document.documentElement.scrollHeight,document.body.scrollHeight); if(_scrollHeight>visibleHeight){ floatDiv = document.createElement("div"); floatDiv.style.top = visibleHeight - 40+"px"; floatDiv.style.left = visibleWidth - 80 +"px"; floatDiv.style.position = "absolute"; floatDiv.style.cursor = "pointer"; floatDiv.onclick = recoverWindow; document.body.appendChild(floatDiv); var floatImg = document.createElement("img"); floatImg.src = "/iKnow/resources/icons/silk/top.png"; floatDiv.appendChild(floatImg); if(window.addEventListener){ //Firefox, document.addEventListener("scroll",scrollHandler,false); }else{ //IE window.attachEvent("onscroll",scrollHandler); } }}//DIV随滚动窗口一起滚动function scrollHandler(){ var _scrollTop = document.documentElement.scrollTop + document.body.scrollTop; var _scrollLeft = document.documentElement.scrollLeft + document.body.scrollLeft; floatDiv.style.top = visibleHeight + _scrollTop - 40 + "px"; floatDiv.style.left = visibleWidth + _scrollLeft - 80 + "px";}//恢复滚动条到窗口开始处function recoverWindow(){ var _scrollTop = document.documentElement.scrollTop + document.body.scrollTop; if(_scrollTop > 0){ window.scrollBy(0,-100); window.setTimeout(recoverWindow,20); }}?