Homogen Cryptography in PHP language

This some code about homogen Cryptography, you can edit the code as you needed. There are 2 files kripto.php and index.php. Which index.php as main page and there are function too call kripto.php. 

include ('kripto.php');

$homofon = null;

if(isset($_POST['text'])&&isset($_POST['submit'])){

       $text = $_POST['text'];

       if($_POST['submit']=="Enkripsi"){

              $homofon = enkripsi($text);

       } else if($_POST['submit']=='Dekripsi'){

              $homofon1 = dekripsi($text);

                     }

}else{

       $text = null;

}

?.>

?>

       

Tugas Kriptografi

       

              

              

                     Substitusi Homofon

              

              

                     Ketikkan Plaintext

                     Hasil dari apa yang anda minta, berikut ini:

              

              

                     <?php echo $text;?>

                     <?php echo $homofon;?>

              

              

                           

                                  

              

              

                     Ketikkan Chipertext disini:

                     Hasil dari apa yang anda minta, berikut ini:

              

              

                     <?php echo $text;?>

                     <?php echo $homofon1;?>