OctoberCms. Shows ajax validation errors in Backend.

oc-bootstrap-ajax-validation-errors.js

(function(){

function showFieldsValidationMessages(jqXHR, $target) {
    if (!$target) {
        $target = $('form').first();
    }
    if (jqXHR.hasOwnProperty('responseJSON')) {
        if (jqXHR.responseJSON['X_OCTOBER_ERROR_FIELDS']) {

            $("span.error").text("");
            $("div.form-group").removeClass('has-error');
            $("div.form-group").addClass('has-success');

            $.each(jqXHR.responseJSON['X_OCTOBER_ERROR_FIELDS'], function(key, val) {
                var $el = $target.find("div[data-field-name='" + key + "']");

                $el.addClass('has-error');
                $el.removeClass('has-success');

                var $err_container = $el.children("span.error");
                if (!$err_container.length) {
                    $err_container = $el.append($(document.createElement('span')).addClass('help-block before-field error').text(val));
                } else {
                    $err_container.text(val);
                }
            });
        }
    }
    return false;
};

$(document).ready(function() {
    $(document).on('ajaxError', function(e, target, status, jqXHR) {
        showFieldsValidationMessages(jqXHR, $(e.target));
    });

    $(document).on('ajaxSuccess', function(e, target, status, jqXHR) {
        $("span.error").text("");
        $("div.form-group").removeClass('has-error');
    });
});

})();

Changed with additional has-success class.