To enable or disable the spell checker in Firefox, follow these steps:
- Open Firefox and click on the menu button (three horizontal lines) in the top-right corner of the browser window.
- From the dropdown menu, select "Options" or "Preferences." This will open the Firefox settings page.
- In the left sidebar of the settings page, click on "General" (or "Writing & Language" in some Firefox versions).
- Under the "Language and Appearance" section, you will find the "Languages" option. Click on the "Check your spelling as you type" checkbox to enable or disable the spell checker.
- If you want to customize the spell checker settings, click on the "Languages and Dictionaries" button. This will open a new window where you can add or remove languages, as well as install additional dictionaries.
- After making any changes, close the settings page, and Firefox will automatically save the settings.
Note: The steps above may vary slightly depending on the version of Firefox you're using.