Update AntiForgery tokens on Ajax request - both Http cookie and form tokens

gistfile1.cs

/// <summary>
/// resets AntiForgery validation token and update a cookie
/// The new antiforgery cookie is set as the results and sent
/// back to client with Ajax
/// </summary>
/// <param name="Request">request from current context</param>
/// <returns>string - a form token to pass to AJAX response</returns>
private string UpdateRequestVerificationToken(HttpRequestBase Request)
{
    string formToken;
    string cookieToken;
    const string __RequestVerificationToken = "__RequestVerificationToken";
    AntiForgery.GetTokens(Request.Form[__RequestVerificationToken], out cookieToken, out formToken);
    if (Request.Cookies.AllKeys.Contains(__RequestVerificationToken))
    {
        HttpCookie cookie = Request.Cookies[__RequestVerificationToken];
        cookie.HttpOnly = true;
        cookie.Name = __RequestVerificationToken;
        cookie.Value = cookieToken;
        Response.Cookies.Add(cookie);
    }
    return formToken;
}

gistfile2.cs

// within an action construct AJAX response and pass updated token to client
return Json(new
  {
      stat = "ok",
      redirectUrl = successUrl,
      __RequestVerificationToken = UpdateRequestVerificationToken(Request)
  });

gistfile3.js

// update verification token in the form created by Ajax/Mvc
$form.find('input[name="__RequestVerificationToken"]').val(ajax.__RequestVerificationToken);