function openPop(url, width, height, s)
{
	x = (640 - width)/2;
	y = (480 - height)/2;
	if (screen) {
		x = (screen.availWidth - width) / 2;
		y = (screen.availHeight - height) / 2;
	
		if (height > screen.availHeight) {
			height = screen.availHeight - 100;
			width = width + 18;
			s = 1;
		}
	}
		
	window.open(url, '', 'scrollbars=' + s + ',status=0,resizable=0,width=' + width + ',height=' + height + ',screenX=' + x + ',screenY=' + y + ',top=' + y + ',left=' + x);
}