On Chrome for Desktop and Android we have more or less the following logic:

- When a form is filled with data and we observe an XMLHttpRequest we monitor the form via the MutationObserver.
- If the form is taken out of the DOM or made invisible, we ask the user whether they want to save the credentials.

This currently does not work for iOS. Example websites are
- https://www.thinkpacifica.com/app#/app/login
- https://nimia.com

Details on the desktop fix can be seen here in  bug 710431 .