set focus to the next text box

<form action="" method="post">
     <h4>change focus</h4>

    <input type="text" class="change_focus" name="textboxnumber-0" />
    <input type="text" class="change_focus" name="textboxnumber-1" />
    <input type="text" class="change_focus" name="textboxnumber-2" />
    <input type="text" class="change_focus" name="textboxnumber-3" />

</form>
<script>
$('.change_focus').keyup(function(e){

        $(this).next('.change_focus').focus();

});
</script>