I'm not sure whether Firefox saved that information. There is a chance that it is in the session history file, especially if you haven't closed that tab yet. To check that:

Open your currently active Firefox settings folder (AKA your Firefox profile folder) using

Help > Troubleshooting Information > "Show Folder" button

Find all files starting with the name sessionstore and copy them to a safe working location (e.g., your documents folder). In order to read a .js file, it is useful to rename it to a .txt file. Or you could drag it to Wordpad or your favorite word processing software.

The script will look somewhat like gibberish, but if you search for a word in your article that doesn't normally appear in web pages, you may be able to find your data.

Any luck?

For the future, you might want to consider this add-on, although I don't know how long it saves data after you submit a form: https://addons.mozilla.org/en-US/fire.../lazarus-form-recovery/.

Yes, I also think that it is not very likely that Firefox has stored that data.

Are you sure that there isn't a maximum number of characters that you can post on the website?

Sometimes such an input form specifies a maximum or the website doesn't accept more than a specific amount.
Other causes can be the use of special (accented) characters that didn't get send properly.
Normally all the text should be send or nothing at all unless some extension or security software is blocking it.

scher2000, thanks for the info! Maybe it will help someone more than me, but I found only a small part of the required information.

Firefox only saves data to the sessionstore.js file every ten seconds, so if you type quickly or have pasted text before closing the tab then not all data may have been saved.

• http://kb.mozillazine.org/sessionstore.js