function openWindow(url, title, x, y, h, w, centered) {
  if (centered == 1) {
    x = (screen.width - w) / 2;
    y = (screen.height - h) / 2;
  }
  newWindow = window.open(url, title, 'height=' + h + ',width=' + w + ',top=' + y + ',left=' + x + ',scrollbars=no,location=no,toolbar=no,resizable=yes,menubar=no');
}