Grammar.com per STANDS4

Check your text and writing for style, spelling and grammar problems everywhere on the web -- It simply provides all the grammar you need to succeed in life! Enhance your writing everywhere on the web!

Grammar.com will make sure your messages, documents, and blog media posts are clear, error-free, and professional. Adding the Grammar.com extension to your browser means that your spelling and grammar will be corrected and verified on your web-based email, Facebook & Twitter, and anywhere else you communicate on the internet.

To use this extension simply select the text you'd like to verify and click on the extension icon. A pop-up window will open with all possible grammar corrections and suggestions for the selected text.

Note: The extension will not work in tabs that were open prior to installation. After installing this extension, either reload your open tabs or restart Firefox.