A sane method for websites to indicate if a password worked or not. And for enough websites to use it that password saving heuristics could be disabled.

When you submit a form with a password and the password is wrong, you're usually taken back to the same form with the same password. The browser is showing you a form that, if it were submitted, would update the same saved password. Yet the popup dialog asking you whether you want to save the previous obviously wrong value is still persisting.

Why would you want that ? It's an incredible useful feature. Now you can't forget that this password didn't work.

But you can store only one not-working password per username and website. Clearly it should support multiple passwords for the same username and website and have a flag "working" or "not working". Bugmenot has this all figured out years ago!

(Also, your username triggers me in a wildcard sort of way.)