$('.my_form [type=submit]').on('click', function(e){
    var form = $(this).parents('form:first');
    var data = form.serialize();
    var action = 'login';
    ShopMODX.Request.run(action, data).
        then(function(resp){
            if(resp.success){
                alertify.success(resp.message || "Вы успешно авторизованы!");
            }
        });
    return false;
});