function popUp(href, width, height)
{
	day = new Date();
	id = day.getTime();
	var x = (640 - width) / 2;
	var y = (480 - height) / 2;
	if (screen)
	{
		y = (screen.availHeight - height) / 2;
		x = (screen.availWidth - width) / 2;
	}
	var newwindow = window.open(href, id, 'toolbar=no,location=no,directories=no,menubar=yes,resizable=yes,scrollbars=yes,width='+width+',height='+height+',screenX='+x+',screenY='+y+',left='+x+',top='+y);
	return newwindow;
}