Untitled

<html>
  <head>
    <meta charset="utf-8">
  </head>
  <body>
    <?php
      if(isset($_POST['data1']) && isset($_POST['data1']))
      {
        $time1 = explode("-",$_POST['data1']);
        $time2 = explode("-",$_POST['data2']);
        $stamp1 = mktime(0, 0, 0, $time1[1], $time1[0], $time1[2]);
        $stamp2 = mktime(0, 0, 0, $time2[1], $time2[0], $time2[2]);

        $outputStamp = abs($stamp1 - $stamp2);
        $outputData = date('d-m-Y',$outputStamp);
        $outputData = explode('-',$outputData);
        $outputData[0]-=1;
        $outputData[1]-=1;
        $outputData[2]-=1970;
        $outputData=$outputData[0].'-'.$outputData[1].'-'.$outputData[2];
        echo $outputData;
        ?>
          <hr>
        <?php
      }
    ?>
    <form action="<?php echo pathinfo(__FILE__)['basename']; ?>" method="post">
      Daty podaj w formacie dd-mm-rrrr<br>
      Podaj date 1: <input name="data1" type="text"><br>
      Podaj date 2: <input name="data2" type="text"><br>
      <input type="submit" value="Oblicz">
    </form>
  </body>
 </html>