Your local HTML script (a HTML file with JavaScript?) generally can't decide whether to send information to an arbitrary server encrypted or not.
Yes it can. Because the local HTML script doesn't send anything. I think you're completely missing the point. My local HTML doesn't interact with the outside world. I don't use it to populate any forms. I use it to determine my password.
I'm assuming your script can help you remember a password to log into, say, your airline customer account you created two years ago in order to change some bookings.
MY SCRIPT REMEMBERS NOTHING. Do you people need a drawing to understand this?
My password is formulated out of a salt (my 'password') and the website I'm booking at.
Say I go back to delta.com to book tickets. I have no clue what my login or password is. But I have a guess: The e-mail is going to be "delta.com@example.com" (I have my own domain) and the password is going to be an 8 character substring from: sha1(md5(hunter2delta.com))
I have a Javascript implementation because it is the easiest. I have a little bookmarklet with the code in it. I have a bash implementation. I've written implementations in other stuff but use the Javascript the most because I use the password maker on the web the most.
I know it's not 'grease monkey'. I haven't used GreaseMonkey since I switched to Chrome years ago. It's not that funny. You see people write MAC or mbps. I haven't used GreaseMonkey in long enough to remember the proper camelcase.