Yes, you can use the Master Passoword:

• Use a Master Password to protect stored logins and passwords

You save your users and password and protect its by a Master Password!

EDIT: I did a search and a found some addons:

• iMacros for Firefox
• QuickPasswords
• Addons Search 1
• Addons Search 2

Hmmm... Yes, I use a Master Password. But I can't see how that is that related to my question. Maybe you should read that article I posted from MacFixIt?

Websites may be using autocomplete=off to prevent Firefox from saving form data like name and password.

You can remove autocomplete=off with a bookmarklet to make Firefox store form data like names and passwords.

• http://kb.mozillazine.org/User_name_and_password_not_remembered

Note that Firefox won't auto-fill saved form data automatically when autocomplete=off is used, so you need to double-click the empty name field to get a drop-down list.

Thanks a lot, cor-el. This seems to be the right thing, looks similar to that SiteSearch bookmarklet I've been using for ages. When I come across a problematic site (not, as the article on Safari wisely points out, a bank or similar, where I do not want the password remembered), I'll let you know how it works.

I was quite aware of the drop-down list, and I do use its capabilities. Some banks even let you use them for different accounts, but there are other, quite ordinary sites that stubbornly only you a blank user name field. Or others where you have to remember and digit the first letter or number of your user name to even get the drop-down.

Sorry, Diego, but managing passwords is not the problem, I'm doing fine there, thank you. And unfortunately, I'm a bit short on time to begin browsing through all the features in the list of addons you've past to me. So I'll try cor-el's bookmarklet first.

hello tingo, this is something that can prospectively set within firefox itself from version 29 and onwards: www.ghacks.net/2013/12/24/firefox-29-save-fill-autocompleteoff-passwords/

for the moment you could also use an addon like https://addons.mozilla.org/firefox/addon/remember-passwords/ to achieve that more conveniently.

That sounds even better (sorry to Diego and cor-el). Will try on first occasion and get back to the thread. Thanks!

If you use the bookmarklet (saved as a bookmark) then it might be more effort, but you are aware that the website has made a restriction on storing this data. With the extension everything happens unnoticed in the background. I don't know if the extension also works in other cases where saved form data is involved or only for input fields or forms with a password field. The bookmarklet can also help with storing saved form data in specific cases.

Thanks again, I'll keep that in mind too. Small problem with the bookmarklet, I figure, is that you have to remember yourself that you've been on that site and that it has "forgotten" your username or password or both after your last visit. I've come across some of these (which is why I asked the question in the first place), but they are far in between (which is why I can't remember one offhand, so I'm waiting to come across one to try those solutions). In the vast majority of cases things are clear-cut, I believe: they remember the data, or I tell them (banks, typically) not to.

You can right-click an input field and open the built-in Inspector via "Inspect Element" to check if there is an autocomplete=off attribute present on this input field. Sometimes this attribute is set on the form and not on the input field.

You can use a bookmarklet with this JavaScript code to check if there are input fields with the autocomplete attribute.
The result is also displayed in the Web Console (Firefox/Tools > Web Developer;Ctrl+Shift+K) (you can choose to leave out console.log(T) or alert(T)).

javascript:(function(){var c=0,e=document.querySelectorAll('input[autocomplete],form[autocomplete]'),T=[];
for(i=0;E=e[i];++i){T.push('['+(++c)+'] '+(E.name||'#'+E.id)+' ('+(V=E.getAttribute('autocomplete').toLowerCase())+')');}
T.unshift('autocomplete: '+c);
T=T.join('\n');
console.log(T);
alert(T);})();

I'll check that too, thanks

Hello good folks,

Sorry for taking so much time getting back to you all, but besides banks such sites are rather far in between. So far I've come across 4 of them. Having installed the Remember Passwords suggested by philipp and using the scripts proposed by cor-el in three of those cases, this is what I got:

In two of the cases, nothing. The sites refuse obstinately to remember anything, including the user name. No drop-down list came to save me, not even writing the first letter or number of the user name (which in certain cases reveals a one-item drop-down list — takes knowing something of your user name, of course).

In the third case, a site where originally the password had been remembered but not the user name, nothing had changed, apparently, at next login. But curiously, clicking on the Check Password bookmarklet made the user name magically appear.

The fourth case was Yahoo Mail, which periodically resets its automatic log-in feature. For the first time today the password field was filled in. As I hadn't even got to use the bookmarklets yet, I imagine that it's the addition that did its work, unexpectedly.

I'll be back with more, when available.

In same cases websites actually overlay the input form with another element as a place holder, so that the real field is hidden.
The Firefox Password Manager and form save may not work in cases like this when an input field is hidden.
The Yahoo log in page uses autocomplete=off, so you need to use an extension or bookmarklet to remove the autocomplete to make Firefox remember a new name and password.

As a last resort you can add the name and password manually yourself to have it at least stored in case you have forgotten it.

• Saved Password Editor: https://addons.mozilla.org/firefox/addon/saved-password-editor/

This one seems interesting too, but apparently it takes time figuring out, time which I don't have much of right now. But I'll get back to you, ubless v.29 is out before and does miracles all of its own.

This Saved Password Editor appears to be more suited to the task, quite comprehensive indeed — if one can call a valid sample the 3 sites I've used it with so far. Two of then responded perfectly well, one actually a bit surprisingly as both the username and password tags were a long string that looked like a generated key. But that wasn't the case, apparently.

In the third case — a bit ridiculous, as nothing overly sensitive can come out of that particular site — SPE couldn't recognize a login form at all. Taking a look at the page's source, there was, matter of fact, nothing at all there. Problem explained here:

Sites known not to work with the password manager - Google Groups

with a possible workaround with another add-on called iMacros, which I'm leaving for a later time.

Great progress with this add-on, also has an excellent tutorial video at:

HOWTO - Saved Password Editor 2.5 - YouTube

Thanks for all the help!