function popup(url,w,h,menu) {
	x = Math.floor((screen.width - w) / 2);
	y = Math.floor((screen.height - h) / 2);        
	features = "screenx="+x+",screeny="+y+",left="+x+",top="+y+",width="+w+",height="+h+",location=no,resizable=yes"+",directories=no,status=no,scrollbars=yes";

	if (menu != null) {
		features += ",menubar=yes,toolbar=yes";
	} else {
		features += ",menubar=no,toolbar=no"; 
	}
	window.open(url,"newwin",features);
}