How do I make Firefox 4 save passwords without asking?

Question

This is not a duplicate, the original question covers versions of Firefox before 3.6. The way Firefox has been designed in these newer versions is fundamentally different from how it was in that older question.

Answer 1

via Raymond.cc

In Firefox 4, the developers have packed all of the naked files into one jar file called omni.jar.

[...]

All you need to do is extract the omni.jar file with WinRAR or rename it to omni.zip and use the Windows 7 to extract it. Then make any modification or changes to the files, ZIP it back again and copy to Firefox folder.

You can go ahead and edit the nsLoginManagerPrompter.js to auto save password without prompting the user or edit the nsLoginManager.js to allow saving of password into the built-in password manager on login forms with autocomplete=”off”.

Answer 2

As far as I know, it's now impossible to do so as of Firefox 4. It's a question of safety (the built-in password manager is really unsafe!). I recommend using an add-on like Lastpass, but note that it still won't save any passwords without asking.