Kind of a useless addon... it takes you to a website where you can see the errors but it does not clearly show the correct spelling of those words.

It is far quicker just to use another service such as google.

Except for the constant ads that tell me I would need to pay for an upgrade just to see other errors, I would have rated it higher. I am almost ready to report it for abuse.

I created my profile just to give 5 stars. But only active when necessary. I think browsing with it on means delivering a lot of data.

Add-on này cực tốt luôn không những thế còn miễn phí với MNM nữa không có gì để chê cả quá tuyệt vời.

Just downloaded it and so far -so good. I managed to set a spell check for 4 languages, which is amazing considering that Firefox by default let you check spelling of only one language. I need 4, and the app is seems to be excellent for that.
You have to add the languages in the app settings. Once you've done that, it works well.

Perfecte, sobretot perquè està en català! ;)

De gran ayuda, a mi me va de perlas.