php online proxy to the code

 
<?php 
if ($_REQUEST['url']) 
{ 
header('Location:http://bcd.allowed.org/0/?url='.base64_encode(strrev($_REQUEST['url']))); 
} 
else 
{ 
echo "<form method='POST' action='proxy.php'> 
url:<input name='url' type='text' value=\"\" /> 
<input type='submit' value=\"go\" /> 
</form>"; 
} 
?>