<style type="text/css">
.float {
width: 100px;
height: 800px;
border: solid 1px white;
}
</style>
</head>
<div style="width: 970px;height: 0px;">
<div id="a" class="float"><a HREF="http://thichnhac.com" TARGET="_blank">
<img src=" http://thichnhac.com/test_float_banner.jpg" border="0"></a></div>
<div id="c" class="float"><a href=" http://thichnhac.com" target="_blank">
<img src=" http://thichnhac.com/test_float_banner.jpg " border="0"></a></div>
</div>
</body>
<script type="text/javascript">
function setPosition(id, position) {
var store = {
ram : {
top : 0,
left : 0,
right : 0,
bottom : 0
},
rom : {
top : null,
left : null,
right : null,
bottom : null
}
};

for (var i in position) {store.rom[i] = position[i];}
var element = document.getElementById(id);
for (i in store) {element[i] = store[i];}
element.rom.move = function() {
if (window.innerHeight) {
var topPage = window.pageYOffset;
var leftPage = window.pageXOffset;
var rightPage = leftPage + window.innerWidth - element.offsetWidth;
var bottomPage = topPage + window.innerHeight - element.offsetHeight;
}
else {
var topPage = document.body.scrollTop;
var leftPage = document.body.scrollLeft;
var rightPage = leftPage + document.body.clientWidth - element.offsetWidth;
var bottomPage = topPage + document.body.clientHeight - element.offsetHeight;
}

element.style.position = "absolute";
if (element.rom.top != null) {
element.ram.top += Math.round((topPage + element.rom.top - element.ram.top)/20);
element.style.top = element.ram.top;
}
if (element.rom.left != null) {
element.ram.left += Math.round((leftPage + element.rom.left - element.ram.left)/20);
element.style.left = element.ram.left;
}
if (element.rom.right != null) {
element.ram.right += Math.round((rightPage - element.rom.right - element.ram.right)/20);
element.style.left = element.ram.right;
}
if (element.rom.bottom != null) {
element.ram.bottom += Math.round((bottomPage - element.rom.bottom - element.ram.bottom)/20);
element.style.top = element.ram.bottom;
}
setTimeout("document.getElementById('"+element.id+"').rom.move()",10);
};
element.rom.move();
}

setPosition("a", {top: 0, left: 910});
setPosition("c", {top: 0, left: 0});

</script>