ASP. NET subdomain with cookie across domains

First, a foreigner's solution:

Http://www.asp.net/web-api/overview/security/enabling-cross-origin-requests-in-web-api

One more brother. Solution Description:

Http://www.cnblogs.com/czcz1024/p/3673136.html

Note the point:

In an MVC project, when adding response header information to the server, it is important to judge Childaction, which is the other action contained in an action, a common case where the childaction is not added to the response header, otherwise the the values of Access-control-allow-origin and access-control-allow-credentials are repeated several times (several childaction are repeated)

The common implementation method is to increase the filter

ASP. NET subdomain with cookie across domains