This add-on was originally a Firefox add-on by goodwill, however it was incompatible with firefox 3.5 (the latest version at the time). I have edited it (I hope goodwill doesn't mind) and will continue to edit it to be compatible with whatever the current version of Firefox is.
If the website takes you to a download for version 0.1.1.6, just know that that version was a beta test (sorry, Mozilla) for version 126.96.36.199 and will not work. However, version 188.8.131.52 will.
Also, some users may need to enable 3rd party cookies. Or so says one of the reviewers.
ALSO NOTE: [email protected] updated goodwill's addon and did a much better job than me, even added more features. You can choose between downloading my version or his version. To get his, do an addon search for "Add N Edit cookies", go to goodwill's, go on his profile, and click [email protected]'s version (0.3)
As you can see, I'm just trying to present you with any options you may prefer.