flash漂浮广告特效

<span id='img' style='position:absolute;'  onmouseover='mystop()' onmouseout= 'start()'><object classid='clsid:D27CDB6E-AE6D-11cf-96B8-444553540000' codebase='http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,29,0' width='200' height='100'><param name='movie' value='http://www.wosowoso.com/google/b1/go1.swf'><param name='quality' value='high'><embed src='http://www.wosowoso.com/google/b1/go1.swf' quality='high' pluginspage='http://www.macromedia.com/go/getflashplayer' type='application/x-shockwave-flash' width='200' height='100'></embed></object></span>
<script language='JavaScript'>
var xPos = 0;var yPos = 0; var step = 1;var delay = 10;var height = 0; var Hoffset = 0;var Woffset = 0; var yon = 0;var xon = 0; var xon = 0; var interval;
var img = document.getElementById('img');
img.style.top = 0;
function changePos(){
width = document.body.clientWidth;
height = document.body.clientHeight;
Hoffset = img.offsetHeight;
Woffset = img.offsetWidth;
img.style.left = xPos + document.body.scrollLeft;
img.style.top = yPos + document.body.scrollTop;
if (yon) {
yPos = yPos + step;

}else {
yPos = yPos - step;
}
if (yPos < 0) {
yon = 1;
yPos = 0;
}
if (yPos >= (height - Hoffset)) {
yon = 0;
yPos = (height - Hoffset);
}
if (xon) {
xPos = xPos + step;
}
else {
xPos = xPos - step;
}
if (xPos < 0) {
xon = 1;
xPos = 0;
}
if (xPos >= (width - Woffset)) {
xon = 0;
xPos = (width - Woffset);
}
}
function start() {
img.visibility = 'visible';
interval = setInterval('changePos()', delay);
}
function mystop()
{
clearInterval(interval)
}
 start()
</script>