function openDialog(theURL,width,height) {
  var top = (screen.height - height) / 2;
  var left = (screen.width - width) / 2;
  var params = "resizable=yes,scrollbars=no,menubar=no,width=" + width + ",height=" + height + ",top=" + top + ",left=" + left;
  window.open(theURL,'Dialog',params);
}