I've noticed that Firefox does not suggest previously used credit card numbers. For example, lets say I have an input field where user is supposed to enter a credit card number. If they enter anything else, the form submits, and if they focus on the field again, it suggest the previously entered value(s), but if they enter a valid credit card number, it is not suggested along with the other suggestions.
I appreciate the detail, since it adds a bit of security, but how is firefox doing that? Does it check all values on all input boxes to see if they seem like a credit card number, and if they do, avoid saving them for later suggestions? Can this behavior be deactivated? And lastly, is Firefox the only browser doing that?