怎样让层随着滚动条下移而下移,上升而上升?

Question

http://www.baron.com.cn/javascript里面能找到你要的东西

Answer 1

将GIF放到一个ID为"border"的层中:<div id="border" style="position:absolute; top:0; left:0; z-index:2;">
<img src="http://go.6to23.com/qingang1983/001/2003081634035280.gif">
</div>然后加入如下代码:<script Language="Javascript">
<!--
//以下是保持border层随窗口内容滚动而自动滚动
function KB_keepItInIE(theName,theWantTop,theWantLeft)
{
theRealTop = parseInt(document.body.scrollTop);
theTrueTop = theWantTop+theRealTop;
document.all[theName].style.top = theTrueTop;
theRealLeft = parseInt(document.body.scrollLeft);
theTrueLeft = theWantLeft+theRealLeft;
document.all[theName].style.left = theTrueLeft;
}function KB_keepItInNN(theName,theWantX,theWantY)
{
theRealLay = document.layers[theName];
theBadX = self.pageYOffset;
theBadY = self.pageXOffset;
theRealX = theBadX+theWantX;
theRealY = theBadY+theWantY;
theRealLay.moveTo(theRealY,theRealX);
}IE4 = (document.all) ? 1 : 0;
NN4 = (document.layers) ? 1 : 0;
if (document.all.border)//检测当前页面中是否有ID为"border"的层
{ if (IE4)
{
setInterval('KB_keepItInIE("border",0,0)',1);
} if (NN4)
{
setInterval('KB_keepItInNN("border",0,0)',1);
}
}
//-->
</script>

Answer 2

document.body.scrollTop//滚动条向下滚动的距离
document.body.scrollLeft//滚动条向右滚动的距离
document.body.scrollLeft+div.style.posLeft//当前层Left位置
document.body.scrollTop＋div.style.posTop//当前层Top位置