[COD]: Link Reverse PHP

<?php
    //  @Author: [iPs]SuYaNw / Converta URL de sites ( PHP ).

    $rev = "";
    echo "<center><img src='http://img542.imageshack.us/img542/9450/linkrev.png'/><br><font size='2'>By: <b>SuYaNw</b></font><hr width='300' align='center'>

            <form action='' method='POST'>
                Url:<input type='text' name='urlconv' alt='coloque aqui um edereço para ser convertido'>
                <input type='submit' name='envia' value='Converter' alt='Clique aqui para converter'>
            </form>";

    if(isset($_POST['envia']))
    {
        $pe = $_POST['urlconv'];
        if($pe == NULL)
        {
            echo "Coloque ali encima algum LinK!";
            echo "<br><hr width='300' align='center'><font size='2'>This project was created by SuYaNw.</font></center>";
            return false;
        }
        $rev = strrev($pe);
        echo "Link Convertido: <input type='txt' value='$rev'><br><a href='$rev'>Ir para este site</a>";
    }

    echo "<br><hr width='300' align='center'><font size='2'>This project was created by SuYaNw.</font><br>
    <a href='http://www.morologoali.blogspot.com/'>Moro Logo Ali Downlodas</a></center>";
?>