如何将底部做成漂浮元素，永远都在屏幕的下方，不随屏幕滚动。

用 position:fixed
注意，IE6不支持这种定位，需用 position:absolute 和 JS控制位置代替
看看这里
http://dancewithnet.com/2007/04/19/cross-brower-css-fixed-position/
<html>
<head>
<title>float div</title>
<style type="text/css">

</style>
</head>
<body style="overflow-x: hidden">
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
<div id="floater" style="width: 100%; top: 341px">
<table width="100%" border="0" cellspacing="0" cellpadding="0"
align="right">
<tr>
<td height="20" align="right">
<img style="vertical-align: middle;" src="#" alt="float img"/>
</td>
</tr>
</table>
</div>
<script type="text/javascript">
self.onError=null;
currentX = currentY = 0;
whichIt = null;
lastScrollX = 0; lastScrollY = 0;
NS = (document.layers) ? 1 : 0;
IE = (document.all) ? 1: 0;
alert(NS + "-" + IE);

function heartBeat() {
if(IE) { diffY = document.body.scrollTop; diffX = document.body.scrollLeft; }
if(NS) { diffY = self.pageYOffset; diffX = self.pageXOffset; }
if(diffY != lastScrollY) {
percent = .1 * (diffY - lastScrollY);
if(percent > 0)
percent = Math.ceil(percent);
else
percent = Math.floor(percent);
if(IE)
document.all.floater.style.pixelTop += percent;
if(NS)
document.floater.top += percent;
lastScrollY = lastScrollY + percent;
}
if(diffX != lastScrollX) {
percent = .1 * (diffX - lastScrollX);
if(percent > 0)
percent = Math.ceil(percent);
else
percent = Math.floor(percent);
if(IE)
document.all.floater.style.pixelLeft += percent;
if(NS)
document.floater.left += percent;
lastScrollX = lastScrollX + percent;
}
}


function checkFocus(x,y) {
stalkerx = document.floater.pageX;
stalkery = document.floater.pageY;
stalkerwidth = document.floater.clip.width;
stalkerheight = document.floater.clip.height;
if( (x > stalkerx && x < (stalkerx+stalkerwidth)) && (y > stalkery && y < (stalkery+stalkerheight)))
return true;
else
return false;
}
function grabIt(e) {
if(IE) {
whichIt = event.srcElement;
while (whichIt.id.indexOf("floater") == -1) {
whichIt = whichIt.parentElement;
if (whichIt == null) {
return true;
}
}
whichIt.style.pixelLeft = whichIt.offsetLeft;
whichIt.style.pixelTop = whichIt.offsetTop;
currentX = (event.clientX + document.body.scrollLeft);
currentY = (event.clientY + document.body.scrollTop);
} else {
window.captureEvents(Event.MOUSEMOVE);
if(checkFocus (e.pageX,e.pageY)) {
whichIt = document.floater;
StalkerTouchedX = e.pageX-document.floater.pageX;
StalkerTouchedY = e.pageY-document.floater.pageY;
}
}
return true;
}
function moveIt(e) {
if (whichIt == null) {
return false;
}
if(IE) {
newX = (event.clientX + document.body.scrollLeft);
newY = (event.clientY + document.body.scrollTop);
distanceX = (newX - currentX); distanceY = (newY - currentY);
currentX = newX; currentY = newY;
whichIt.style.pixelLeft += distanceX;
whichIt.style.pixelTop += distanceY;
if(whichIt.style.pixelTop < document.body.scrollTop)
whichIt.style.pixelTop = document.body.scrollTop;
if(whichIt.style.pixelLeft < document.body.scrollLeft)
whichIt.style.pixelLeft = document.body.scrollLeft;
if(whichIt.style.pixelLeft > document.body.offsetWidth - document.body.scrollLeft - whichIt.style.pixelWidth - 20)
whichIt.style.pixelLeft = document.body.offsetWidth - whichIt.style.pixelWidth - 20;
if(whichIt.style.pixelTop > document.body.offsetHeight + document.body.scrollTop - whichIt.style.pixelHeight - 5)
whichIt.style.pixelTop = document.body.offsetHeight + document.body.scrollTop - whichIt.style.pixelHeight - 5;
event.returnValue = false;
} else {
whichIt.moveTo(e.pageX-StalkerTouchedX,e.pageY-StalkerTouchedY);
if(whichIt.left < 0+self.pageXOffset)
whichIt.left = 0+self.pageXOffset;
if(whichIt.top < 0+self.pageYOffset)
whichIt.top = 0+self.pageYOffset;
if( (whichIt.left + whichIt.clip.width) >= (window.innerWidth+self.pageXOffset-17))
whichIt.left = ((window.innerWidth+self.pageXOffset)-whichIt.clip.width)-17;
if( (whichIt.top + whichIt.clip.height) >= (window.innerHeight+self.pageYOffset-17))
whichIt.top = ((window.innerHeight+self.pageYOffset)-whichIt.clip.height)-17;
return false;
}
return false;
}
function dropIt() {
whichIt = null;
if(NS)
window.releaseEvents (Event.MOUSEMOVE);
return true;
}

if(NS) {
window.captureEvents(Event.MOUSEUP|Event.MOUSEDOWN);
window.onmousedown = grabIt;
window.onmousemove = moveIt;
window.onmouseup = dropIt;
}
if(IE) {
document.onmousedown = grabIt;
document.onmousemove = moveIt;
document.onmouseup = dropIt;
}
if(NS || IE)
action = window.setInterval("heartBeat()",1);
</script>
</body>
</html>

调试易

如何将底部做成漂浮元素，永远都在屏幕的下方，不随屏幕滚动。

解决方案 »