fatto..

codice:
function handleEnter (field, event) {
		var keyCode = event.keyCode ? event.keyCode : event.which ? event.which : event.charCode;
		if (keyCode == 13) {
			var i;
			for (i = 0; i < field.form.elements.length; i++)
				if (field == field.form.elements[i])
					break;
			i = (i + 1) % field.form.elements.length;
			field.form.elements[i].focus();
			return false;
		} 
		else
		return true;
	}