Using the spell checker
Firefox automatically checks the spelling of words that you enter in text boxes containing more than one line. As soon as you finish typing a word, it is checked against the words in the installed dictionary. If the word is not found in the dictionary, it will be underlined in red, as in the following example:
- Note: Automatic spell-checking is only turned on for text boxes containing more than one line, where you can enter as much text as you want.
Table Of Contents
- Disabling automatic spell-checking
- Correcting misspelled words
- Adding dictionaries
- Switching dictionaries
- Removing a word you have accidentally added
Disabling automatic spell-checking
By default, Firefox is configured to automatically check spelling. You can turn it off in the OptionsPreferences window:
- At the top of the Firefox windowOn the menu bar, click on the ToolsFirefoxEdit menu, and select Options...Preferences....
- Select the Advanced panel.
- Click the General tab.

- Select Check my spelling as I type.
- Click Close the preferences window.
Correcting misspelled words
When spell-checking is enabled, you can easily correct misspelled words. To correct the misspelled word, right-clickhold down the Ctrl key while you click on it and select one of the suggested words at the top of the menu.
If none of the suggested words is appropriate, you must manually edit it. If you are sure the word is spelled correctly, you can add it to the dictionary. To add a word to the dictionary, right-clickhold down the Ctrl key while you click on it, and select Add to Dictionary.
Adding dictionaries
You can install other dictionaries as necessary.
- Right-clickHold down the Ctrl key while you click in any text box containing more than one line.
- Select Languages.
- Select Add dictionaries....
- The Mozilla Add-ons Dictionaries page is displayed. To add a dictionary to your Firefox installation, click the "Install Dictionary" link next to the dictionary you want to add. The Software Installation window appears. When it is displayed, click , which should open the Add-ons window, where you'll see the dictionary being installed.

- To enable the dictionary, click the button, in the Add-ons window.
Switching dictionaries
After the dictionary is installed, you can switch to it, as needed. To switch to a different installed dictionary, right-clickhold down the Ctrl key while you click in a multi-line field, select Languages, then select the dictionary you want to use.
Removing a word you have accidentally added
- Open your profile folder:
- (Firefox 3.0 and 3.5): See How to find your profile
- (Firefox 3.6): At the top of the Firefox windowOn the menu bar, click on the Help menu and select Troubleshooting Information.... The Troubleshooting Information tab will open.
- Under Application Basics, click on .
- From the menu at the top of the Firefox windowbar, select FileFirefox and then select the ExitQuit FirefoxQuit menu item.
- Open the file persdict.dat in a text editor. (Such as Wordpad)
- In the text editor each word you've added is on a separate line. Remove the line, containing the word you wish to remove.
- Click the File menu, and select Save, to save your work.
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