<script type='text/javascript' src='http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js?ver=1.3.2'></script>
<script type="text/javascript">
    $(document).ready(function(){
$("input").not( $(":button") ).keypress(function (evt) {
if (evt.keyCode == 13) {
iname = $(this).val();
if (iname !== 'Submit'){
var fields = $(this).parents('form:eq(0),body').find('button, input, textarea, select');
var index = fields.index( this );
if ( index > -1 && ( index + 1 ) < fields.length ) {
fields.eq( index + 1 ).focus();
}
return false;
}
}
});
    });
</script>

If you need some html code to test it with, you can use:

<form id="form1" name="form1" method="post" action="http://www.disney.com">

<label>
<input type="text" name="textfield" id="textfield" />
</label>
<label>
<input type="text" name="textfield2" id="textfield2" />
</label>
<label>
<input type="text" name="textfield3" id="textfield3" />
</label>

<label>
<input type="submit" name="button" id="button" value="Submit" />
</label>
</form>

If you’d prefer, you can try a live demo of the Enter to Tab on this site.