<script language="javascript">
var x=0,y=0,w=200,h=200;
var dx=5,dy=5;
var interval = 100;
var win=window.open('javascript:"<h1>BOUNCE!</h1>"',"","width="+w+",height="+h);
win.moveTo(x,y);
var intervalID = window.setInterval("bounce()",interval);
function bounce(){
if (win.closed) {
clearInterval(intervalID);
return;
}
if ((x+dx> (screen.availWidth-w)) || (x+dx <0)) dx=-dx;
if ((y+dy> (screen.availHeight - h)) ||(y+dy<0)) dy=-dy;
x+=dx;
y+=dy;
win.moveTo(x,y);
}