function centeredWindow(url,winname,w,h) {
	windowleft = (screen.width - w)/2;
	windowtop = (screen.height - h)/2;
	settings = '"toolbar=no,directories=no,menubar=no,scrollbars=yes,resizable=yes,status=no,width='+w+',height='+h+ ',left='+windowleft+',top='+windowtop+'"';
	newWin = window.open(url, winname, settings);
	newWin.focus();
}