function pop_win(url,width,height){

	// so that we don't always pop the url into the same window...
	var rnd = ""+Math.round(Math.random(0,100)*1000);

	var x = (screen.availWidth - width)/2;
	var y = (screen.availHeight - height)/2;
	var w = window.open(
		url,
		('window'+rnd),
		('toolbar=no,scrollbars=yes,resizable=no,menubar=no,status=no,directories=no,location=no,width='+width+
		',height='+height+',screenX='+x+',screenY='+y+',left='+x+',top='+y)
	);
	w.focus();
	return w;
}