Get Access Token Cross-Domain Sites

So our company setup has several application which use Okta. We have created a single sign-in page which is using the Okta widget. We are customizing the redirect uri based on the origin uri. One of the application needs to use the access token to call a web api for authorization. Since the login page is on a different domain ( than the application ( what would be the best approach to accessing the access token?

The login page is built is using Java (JSP) and Okta widget (JavaScript). The application is built on ASP.NET 4.6.2 Forms Authentication using VB.NET. Currently the way authentication works is the user authenticates with Okta through the widget. An internal token is generated and passed to the application. This token is used to forms authenticate with .NET. As far as I can tell there is no access to the original Okta id or access tokens.