// -------------------------------------------------------------------------
// Open PopUp function; window can be centered, size limited to screen size
// -------------------------------------------------------------------------
function openPopUp(url, name, w, h, flags)
{
  //flags = 'directories=yes,location=yes,menubar=yes,scrollbars=yes,status=yes,toolbar=yes,resizable=yes';
  
  w = (w > screen.availWidth) ? screen.availWidth - 40 : w;
  h = (h > screen.availHeight) ? screen.availHeight - 120 : h;
  var winX = (screen.availWidth - w)*.5;
  var winY = (screen.availHeight - h)*.5;

  // if (popupWin && !popupWin.closed) popupWin.close();
  popupWin = window.open(url, name, 'width=' + w + ',height=' + h + ', left=' + winX + ',top=' + winY + ',screenX=' + winX + ',screenY=' + winY + ',' + flags);

  popupWin.focus();
}