Ginger is the number one contextual grammar and spell checker! Install it and watch your typos, spelling mistakes and grammar mistakes disappear from Firefox in one click!
Here is a little more information about this grammar and spell checker for Firefox:
Ginger’s contextual grammar checker and spell checker takes writing in your Firefox browser to the next level! Install and watch your spelling typos, grammar errors and misused words disappear from your Firefox browser in one simple click. Ginger proofreads your writing in popular websites such as Gmail, Facebook, LinkedIn and many others.
Ginger is the only proofreader that corrects 30 types of grammatical errors. Try it out! You can pick up Ginger at the Firefox Add-ons website.