Use bonpatron on all the websites you want.
"BonPatron" is a grammar checker that finds common spelling errors and grammatical mistakes in French, English and Spanish.
Non registered users can correct 3 texts for free every day. If you have an account on bonpatron.com you can use this extension with no limits.
Correct your French, English and Spanish texts with BonPatron. You can use this extension on any textarea present on a web page. Just open the context menu and click on BonPatron. Have fun!