There are many excellent plugins for Firefox, one of them is Lazarus: Form Recovery. In short, it saves typed forms, so if the browser crashes, a simple click brings back the old text. It has happened to me more than once that i spent quite some time formulating a post only to have all the work get lost on a crash or the website error. I resorted to using Notepad to save text where possible. Now it's just a couple clicks away.
I contacted the author with two requests, to remove the icon from the context menu and to collapse both options into one sub-menu so my context menu is a little less cluttered. He implemented the first as an add-on and sent me a beta, the second was a a bit more complicated and might make it into a new release soon.
I asked what i could do to help. He asked that i spread the word. No problem with that, this is a really good add-on.