simple CORS

nginx.conf

server {
    set $cors_origin "";
    set $cors_cred   "";
    set $cors_header "";
    set $cors_method "";

    if ($http_origin ~* "^http.*\.yourhost\.com$") {
            set $cors_origin $http_origin;
            set $cors_cred   true;
            set $cors_header $http_access_control_request_headers;
            set $cors_method $http_access_control_request_method;
    }

    add_header Access-Control-Allow-Origin      $cors_origin;
    add_header Access-Control-Allow-Credentials $cors_cred;
    add_header Access-Control-Allow-Headers     $cors_header;
    add_header Access-Control-Allow-Methods     $cors_method;
}