function open_popup_window(url,w,h) {
	var winW = w;
	var winH = h;
	var winTop = (screen.height-winH)/2;
	var winLeft = (screen.width-winW)/2;
	
	window.open(url, "SecondaryWindow", 
				"width="+winW+
				",height="+winH+
				",top="+winTop+
				",left="+winLeft+
				",location=no,menubar=no,directories=no,toolbar=no"+
				",scrollbars=yes,resizable=yes,status=no");
}