if($_GET['edit']!=''){<>//edycja
  if($_GET['edit']=='01'){
    $file = "cos/$year/$vid.php";
    $plik = fopen($file, "r");
    $txt_plik = fread($plik, filesize($file));
               fclose($plik);
  echo "
    <a href='cos&year=$year&vid=$vid&edit=01'>edit</a>
    <form action='cos?dir=cos&year=$year&vid=$vid&edit=02' method='post'>
    <button type='submit' class='link'><span>save</span></button>
    <textarea rows='36' cols='75' class='text' type='text' name='source' value=''>$txt_plik</textarea>
    </form>";
  }
  if($_GET['edit']=='02'){
    $txts = $source;
      echo $txts;                             //test poprawnosci zapisu
    $file = "cos/$year/$vid.php";
    $plik = fopen($file, "w");
      fputs($plik, $source);
      fclose($plik);
  }
}