title: Unauthorized result in ajax requests
body: <p>I have application with many ajax actions (implemented using JQuery.ajax), that returns JSON ot html. Some of them should be accessible only to authorized users, and I decorated them with <code>[Authorize]</code> attribute. For not ajax actions, if user not authorized - system redirects him to login page (that configured in web.config). </p>
  
  <p>But this is not applicable for ajax actions, because if user was authorized - he load page, after that cookie expires and he is not authorized, and instead of html block, that should replace old, he get my login page inside block. </p>
  
  <p>I know that I can solve this problem manually, for example remove [Authorize] attribute, and return special json/empty html, if user no authorized. But I dislike this solution, because I need to rewrite all my actions and ajax functions. I want global solution, that allow me not to rewrite my actions (may be custom authorize attribute, or some http unauthorized result custom handling).</p>
  
  <p>I want to return status code, if request is ajax, and redirect to login page, if request isn't ajax.</p>