function open_win(plik, w, h, scroll)
  {

   if (window.screen.availwidth)
    {
      aw=window.screen.availwidth;
      ah=window.screen.availheight;
    }
    else
    {
      aw=window.screen.width;
      ah=window.screen.height;
    }
    ustawienia=
      "left="+(aw-w)/2+","
      +"top="+(ah-h)/2+","
      +"screenX="+(aw-w)/2+","
      +"screenY="+(ah-h)/2+","
      +"width="+w+","
      +"height="+h+","
      +"toolbar=no,"
      +"location=no,"
      +"directories=no,"
      +"status=no,"
      +"menubar=no,"
      +"scrollbars="+scroll+","
      +"resizable=no";
      noweokno=window.open(plik,'nowe',ustawienia);
      if (!noweokno) {
         return false;
      }
      noweokno.focus();
  }