Eviter de réactualiser lors du clik

<?php
    include "includes/func_code.php";
?>
  
<form name="form" method="post" action="" style="text-align:center;">
    <textarea name="text" cols="50" rows="20"></textarea><br/>
    <input type="submit" />
</form>
<div>
<?php
    if(isset($_POST['text'])){
        echo zcode($_POST['text']);
    }
?>
</div>