title: open authentication cross domain redirection issue
body: <p>i am trying open authentication first time in mvc-web-api4 . i have hosted my services in services.domain.com , and front end (UI) is in test.domain.com . </p>
  
  <p>in front end i will call the service to login from facebook. after successful login i will get the access token in services.domain.com . but my code is in test.domain.com. </p>
  
  <p>after redirection from facebook . i am getting access token in service.bubblesbuy.com , but i need that access token in test.domain.com.  </p>
  
  <p>here are the steps i followed </p>
  
  <pre><code>$.ajax({
      url: "services.domain.com/api/Account/ExternalLogins?returnUrl=%2F&amp;generateState=true",
      success: function (data) { 
      //after successful 
      }
  </code></pre>
  
  <p>after successful , i will get providers , here is the output</p>
  
  <pre><code>[     
  {
  "Name": "Facebook",
  "Url": "/api/Account/ExternalLogin?provider=Facebook&amp;response_type=token&amp;client_id=self&amp;redirect_uri=services.domain.com&amp;state=bzDUygFiUw-jOYHCYaDPT8iawAjq1ejd0hmkVPZTwjk1",
  "State": "bzDUygFiUw-jOYHCYaDPT8iawAjq1ejd0hmkVPZTwjk1"
  }
  ]
  </code></pre>
  
  <p>i will pass Url to my service </p>
  
  <pre><code>services.domain.com//api/Account/ExternalLogin?provider=Facebook&amp;response_type=token&amp;client_id=self&amp;redirect_uri=services.domain.com&amp;state=bzDUygFiUw-jOYHCYaDPT8iawAjq1ejd0hmkVPZTwjk1",
  "State": "bzDUygFiUw-jOYHCYaDPT8iawAjq1ejd0hmkVPZTwjk1
  </code></pre>
  
  <p>i am getting the access token in </p>
  
  <pre><code>services.domain.com/#access_token= Hu2B5WmmZLy8TfJ3RqRsVnQDfDcHSiVCMliWrS554PpU-i_LQzdMggJgXClsf-ZtYXRDxxct7m3frZxYR0MKLxNWHwH1gXxi7Y-HUbWjyB9QvBJMwifFCVMnt7BOOlKjJPEAhdOY7ZgRB-vURBH-hHT6wFSXJvvpYpZ0fziX0DgKrLIqUj8&amp;token_type=bearer&amp;expires_in=1209600&amp;state=24HUa-Upzo-_Xh2j0CkAx5TVPdoirvNrGktpg5H5Ifg1
  </code></pre>
  
  <p>but i need to access that token in test.domain.com (front end where my all html page is there )</p>
  
  <p>please help me how to get that access token in test.domain.com (in front end )</p>