Launches a login modal to authenticate with Supercast. This does nothing if the user is already logged in.
Syntax:
Supercast.startLogin()
Parameters:
None
Detecting a login
When the user has succesfully logged in, Supercast will fire a supercast-login-state-changed event to the window DOM Object that it is hosted in.
If you're using <supercast-gate> to gate logged in functionality, that component will automatically refresh itself when the user is logged in.