Open browser in Android Captive Portal after sign in

Question

I am making a captive portal for Android:

1. the user connect to Wi-Fi
2. the captive portal open with informations for login (302 of /generate_204)
3. I post the informations and release the user to use internet (204 of /generate_204)
4. THE PROBLEM: the captive portal close and the browser not open

My purpose is - after the post the informations - release the user, close captive portal and open the browser.

How I do this?

Answer 1

I have tried every option (JavaScript, redirection, different answers for diffirent UserAgents) in every combination, unfortunately I have to conclude that that it isn't possible. (iOS is OK, you just need to window.open() on 4th step)