title: Using Forms authentication cross domain
body: <p>here is our problem..
  We have built an <strong>MVC Web-api</strong> that uses <strong>Forms authentication</strong> with cookies to handle sessions.
  When we use our front-end webpage on the same domain (localhost or web-server) as the web-api, all works fine. (We use JQuery $.get and $.post to communicate with the web-api).</p>
  
  <p>Though the front-end is in the future supposed to be a standalone html5 app, not located on the same domain as the web-api. 
  This isn't working unfortunately.</p>
  
  <p>The web-api does return an authentication cookie to the client, BUT the cookie isn't brought back to the web-api when the front-end sends it's requests.
  When both web-api and front-end are on the same domain, the cookie is automatically sent with the request.</p>
  
  <p>We've tried setting 
  "Access-Control-Allow-Origin: *" and "Access-Control-Allow-Authentication: true" in the web-api webconfig file.</p>