<form method="post">

Žodis: <br/>

<input type="text" size="50" name="md5" /> <br />

<input type="submit" name="sub" value="Generuoti!" />

<p />

Sugeneruota: <br />

<input type="text" size="33" name="generated" value='.$gen.' >

</form>

if($_POST['sub'])

{

    $text = $_POST['md5'];

    $gen = md5($text);

}

else

{

    $gen = "";

}

<?php error_reporting(0); ?>