RemoteModelValidator_JsonResponse.cs

        protected JsonResult RemoteJsonResponseForProperty(string property = null)
        {
            object response;

            if (string.IsNullOrWhiteSpace(property))
            {
                property = System.Web.HttpContext.Current.Request.QueryString.Keys[0];
            }

            if (ModelState.ContainsKey(property) && ModelState[property].Errors.Any())
            {
                response = string.Join(". ", ModelState[property].Errors.Select(e => e.ErrorMessage));
            }
            else
            {
                response = true;
            }

            return Json(response, JsonRequestBehavior.AllowGet);
        }