public ActionResult LogOn(LogOnModel model, string returnUrl)
      {
         if (ModelState.IsValid)
         {
            if (Membership.ValidateUser(model.UserName, model.Password))
            {
               FormsAuthentication.SetAuthCookie(model.UserName, model.RememberMe);
               if (Url.IsLocalUrl(returnUrl))
               {
                  return Redirect(returnUrl);
               }
               else
               {
                  return RedirectToAction("Index", "Home");
               }
            }
            else
            {
               ModelState.AddModelError("", "The user name or password provided is incorrect.");
            }
         }

         // If we got this far, something failed, redisplay form
         return View(model);
      }
      public JsonResult JsonLogOn(LogOnModel model, string returnUrl)
      {
         if (ModelState.IsValid)
         {
            if (Membership.ValidateUser(model.UserName, model.Password))
            {
               FormsAuthentication.SetAuthCookie(model.UserName, model.RememberMe);
               return Json(new { success = true, redirect = returnUrl });
            }
            else
            {
               ModelState.AddModelError("", "The user name or password provided is incorrect.");
            }
         }

         // If we got this far, something failed
         return Json(new { errors = GetErrorsFromModelState() });
      }