Asynchronous authorization on the site and Yandex.mail

Question

Yandex

I attached Yandex.mail for the domain to the site - when registering on the site, the user receives a mailbox in my domain. If authorization on the user's site is successful, it will redirect to Yandex.mail, how to make authorization in the mail happen without a redirect (in the background)?

Description - pdd.yandex.ru/help/section710/
API - pdd.yandex.ru/help/section72/ I

found the registration code here zloy.org/blog/php/122.html , slightly tweaked it for tests codepad.org/ ZDxrv5OW
Here, in addition to registration, you can log in to the mail with the specified login (if one is registered)

Answer 1

Well, the user logs in to the site, and he is thrown into the mail. uncomfortable