They control the client but not Browser/DNS/OS
3 karma · joined August 23, 2014
This state needs to be accessible to all versions of your apps.
As far as my knowledge goes, it is not possible without a central medium. You can either maintain it in a remote server or in a master_domain cookie, to which all apps can redirect, to read current state(similar to SSO).
The second approach is not that clean and you would still need a central server, I would prefer first approach only.
Sharing states/cookies across domains is not supported by browsers due to security concerns. So doing it completely in browser is not possible at moment.