<script type="text/javascript">
function scrollImg()
{ var posX,posY;
if (window.innerHeight) {
posX = window.pageXOffset;
posY = window.pageYOffset; }
else if (document.documentElement && document.documentElement.scrollTop)
{
posX = document.documentElement.scrollLeft;
posY = document.documentElement.scrollTop; }
else if (document.body) {
posX = document.body.scrollLeft;
posY = document.body.scrollTop; }
var ad=document.getElementById("ad");
ad.style.top=(posY+450)+"px";
ad.style.left=(posX+50)+"px";
setTimeout("scrollImg()",0); }
</script>
<div id="ad" style="position:absolute; background:#eeeeee; width:100px; height:100px; border:1px dotted #000; line-height:100px; text-align:center; left: 103px; top: 267px;">scrollImg</div>
<script type="text/javascript"> scrollImg(); </script>问题:如果滚动条到达底部ad.style.top=(posY+450)+"px";上的面的450改成230
function scrollImg()
{ var posX,posY;
if (window.innerHeight) {
posX = window.pageXOffset;
posY = window.pageYOffset; }
else if (document.documentElement && document.documentElement.scrollTop)
{
posX = document.documentElement.scrollLeft;
posY = document.documentElement.scrollTop; }
else if (document.body) {
posX = document.body.scrollLeft;
posY = document.body.scrollTop; }
var ad=document.getElementById("ad");
ad.style.top=(posY+450)+"px";
ad.style.left=(posX+50)+"px";
setTimeout("scrollImg()",0); }
</script>
<div id="ad" style="position:absolute; background:#eeeeee; width:100px; height:100px; border:1px dotted #000; line-height:100px; text-align:center; left: 103px; top: 267px;">scrollImg</div>
<script type="text/javascript"> scrollImg(); </script>问题:如果滚动条到达底部ad.style.top=(posY+450)+"px";上的面的450改成230
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>新建网页 1</title>
</head><body>
<script type="text/javascript">
function scrollImg(){
var posX,posY;
if (window.innerHeight) {
posX = window.pageXOffset;
posY = window.pageYOffset;
}else if (document.documentElement && document.documentElement.scrollTop){
posX = document.documentElement.scrollLeft;
posY = document.documentElement.scrollTop;
}
else if (document.body) {
posX = document.body.scrollLeft;
posY = document.body.scrollTop;
}
var ad=document.getElementById("ad");
var addp=450
if (posY>0)addp=230
ad.style.top=(posY+addp)+"px";
ad.style.left=(posX+50)+"px";
setTimeout("scrollImg()",0);
} </script>
<div id="ad" style="position:absolute; background:#eeeeee; width:100px; height:100px; border:1px dotted #000; line-height:100px; text-align:center; left: 103px; top: 267px;">scrollImg </div>
<script type="text/javascript"> scrollImg(); </script>
<div style=height:1999px></div>
</body></html>