有的网站两边都有图片,图片无论滚动条上下移动都能保持在屏幕的中间位置,这是用什么方法作的呢?请告知一下,最好有代码和说明。谢谢!
把代码贴出来:
// JavaScript Document
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
{/*Netscape stuff*/}
//alert(diffY);
percent=.1*(diffY-lastScrollY);
if(percent>0)percent=Math.ceil(percent);
else percent=Math.floor(percent);
document.getElementById("lovexin12").style.top=parseInt(document.getElementById
("lovexin12").style.top)+percent+"px";
document.getElementById("lovexin14").style.top=parseInt(document.getElementById
("lovexin12").style.top)+percent+"px";
lastScrollY=lastScrollY+percent;
//alert(lastScrollY);
}
suspendcode12="<DIV id=\"lovexin12\" style='left:6px;POSITION:absolute;TOP:100px;'><img src='images/left.jpg' width='100' height='410' style='display:inline'/></div>"
suspendcode14="<DIV id=\"lovexin14\" style='right:6px;POSITION:absolute;TOP:100px;'><img src='images/right.jpg' width='100' height='410' style='display:inline'/></div>"
document.write(suspendcode12);
document.write(suspendcode14);
window.setInterval("heartBeat()",1);