How to Turn Spell Check On or Off in Firefox

We show you three different ways to enable or disable the spell checking feature that checks your spelling in web forms in Mozilla Firefox.

Option 1 – Basic Firefox Menu

1. Select the “Menu”  button located at the upper-right corner of the screen, then choose “Options“.
2. Scroll to the “Language & Appearance” section.
3. Select “Check my spelling as I type” if you want to turn spell checker on. Uncheck it if you wish to have it off.

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Option 2 – From about:config

1. Type “about:config” in the address bar.
2. In the filter field type “spell“.
3. Find the entry for “layout.spellcheckDefault” and double-click it.
4. Set the integer to “1” to “enable”the spell checker. Set the integer to “0” to “disable“the spell checker.

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Option 3 – Via prefs.js file

1. Close Firefox.
2. Navigate to the following location based on your operating system.
   • Windows 10/7/8 – “%APPDATA%\Mozilla\Firefox“
   • Unix/Linux – “~/.mozilla/Firefox“
   • Mac OS X – “~/Library/Mozilla/Firefox” or “~/Library/Application Support/“
3. Open the “Profiles” folder.
4. Open the folder that represents the profile you would like to edit. The name of the folder will vary. It is usually a bunch of characters, followed by “.default”.
5. Open the prefs.js file with a text editor like Notepad.
6. Look for a line that contains “layout.spellcheckDefault“. If it doesn’t exist, add a line for it in the file and set it as desired using these examples:
   • user_pref(“layout.spellcheckDefault“, 1); = Spell Check enabled
   • user_pref(“layout.spellcheckDefault“, 0); = Spell Check disabled