The spell-checking engine is the same one that is provided with the Mozilla Suite / Thunderbird. I have not contributed any code to the spell-checking engine and with the amount of time that it takes to maintain / support SpellBound, I doubt that I ever will. If you experience an issue that is due to the spell-checking engine you can check if there is already a bug report in and if there isn't you can open a new bug in If you are unsure if the issue is due to the spell-checking engine you can review the bugs below for examples of issues that are due to the spell-checking engine. Please read the Dictionaries section below as well since dictionary issues are often mistaken for a spell-checking engine issue.


I do not host or maintain the dictionaries. If you have a question or comment regarding the content of a dictionary you can contact the dictionary author. Often this can be found by downloading the dictionary, decompressing it with what ever utility you use (e.g. WinZip, WinRAR, etc.), and reading the files inside. Updates to dictionaries can be provided to the maintainer of Once again, I do not host or maintain the dictionaries.

How do I use it?

When ever you want to spell check text in a web form first give the form you want to check the focus. For example, if you are already typing in it then it already has the focus. After which you can either access the context menu (e.g. right click, control click for Mac OS X) and choose "Check Spelling" (it will only be displayed in the context menu when elements that you can spell check have focus), press the ctrl/cmd for Mac OS X, shift, and F7 keys simultaneously, or click on the SpellBound button (it will only be enabled when elements that are able to be spell checked have focus and for Firefox users it will only be present if you have added it to your toolbar). If you would like to change the ctrl/cmd+shift+F7 shortcut key combination I recommend using the keyconfig extension.

Some extensions are automatically supported by SpellBound even though you won't see "Check Spelling" in the context menu for the extension. You can find out whether SpellBound will work automatically by pressing the shortcut key as explained earlier or checking whether the SpellBound button is enabled after you have given the element containing the text you would like to check for spelling errors focus by clicking on it.

What versions of Firefox and the Mozilla Suite has SpellBound been tested with?

What is an HTML textarea or input?

A picture or as in this case a demonstration is worth a thousand words. Below are examples.

If you have SpellBound installed you can check the spelling of the input or textarea element by first clicking on one of them and using any of the methods as described in How do I use it?.
A web page can also be integrated with SpellBound in order to provide a button for spell-checking. For more information see the Web Developers page.

This button will spell check the textarea above.

This button will spell check all elements that can be spell checked on this page.

What is an HTML rich text editor?

Check out the Midas Demo on for an example.

Why isn't SpellBound on

With the release of SpellBound 0.7 I plan to place a request for SpellBound to be added. I wanted the code to mature and have the most frequently asked questions available on the web site so that I will be able to support the additional users as well as the addition of Mozilla Suite support prior to making the request. This has turned out to be more problematic than originally expected due to having to support libraries that are different on each operating system / optimized build and significant differences between the trunk and release libraries so it is difficult to say when if ever this will be done.

Does SpellBound work with Thunderbird?

No, but if you can provide me with a good reason to port it to Thunderbird I will. SpellBound is a port of the exact same spell checker as the one used in Thunderbird... it uses the same xul and js files with slight modifications so it will support web forms, it uses the exact same spell-checking engine as the one used by Thunderbird, and they both use the same dictionary files that have been ported from OpenOffice. The only reason it could possibly be useful is if there was an extension in Thunderbird that would benefit from having a spell checker.

Does SpellBound work with Netscape?

Even though I have had some success getting SpellBound to work with Netscape 7.x, Netscape and Mozilla don't utilize the same spell-checking engine so SpellBound will not entirely work with Netscape. In addition, I have tried getting SpellBound to work with the Netscape browser that is based on Firefox but so far I have been unable to get the Mozilla or the Netscape spell check libraries to work with it. I have no plans at present to continue my attempts to get SpellBound to work with Netscape due to lack of success and time constraints but if you are successful please let me know and I will make a version available.

Why doesn't inline spell-checking work directly inside of a form?
Why do I have to launch a spellchecker interface?

This is not a simple thing to accomplish since textarea and input elements do not lend themselves to allowing text decoration and the existing spellchecker interfaces are written to be used with an editor element. The proper way to accomplish this will involve changes to the core of Mozilla and the patch for Bug ID 58612 does exactly that. When this bug is fixed then Mozilla will provide inline spellchecking.

Why does the spellchecker start over at the beginning after editing text?

I am working on allowing it to start from where the cursor was last in the editor and I hope to have a solution in the next release. I hope that it will suffice to say that it has to do with keeping the state of the data known to avoid data loss.

What languages / locales are available with SpellBound?

As of the 0.7.0 release and higher of SpellBound the following languages / locales are included with the extension.
A language / locale is not the same thing as a dictionary. A language / locale changes the language used for the words in the user interface. A dictionary in regards to a spell checker is used to check words for spelling errors.
Afrikaans (af-ZA)
Arabic (ar-SA)
Asturian (ast-ES)
Belarusian (be-BY)
Bulgarian (bg-BG)
Breton (br-FR)
Catalan (ca-AD)
Czech (cs-CZ)
Welsh Cymraeg (cy-GB)
Danish (da-DK)
German (de-AT)
Greek (el-GR)
English, United Kingdom (en-GB)
English, United States (en-US)
Esperanto (eo-EO)
Spanish, Spain (es-ES)
Estonian (et-EE)
Basque (eu-ES)
Persian (fa-IR)
Finnish (fi-FI)
French (fr-FR)
Galician (gl-ES)
Hebrew (he-IL)
Upper Sorbian (hsb-DE)
Hungarian (hu-HU)
Italian (it-IT)
Japanese (ja-JP)
Korean (ko-KR)
Lithuanian (lt-LT)
Macedonian (mk-MK)
Mongolian (mn-MN)
Norwegian Bokmål (nb-NO)
Dutch (nl-NL)
Norwegian Nynorsk (nn-NO)
Sotho Northern (nso-ZA)
Polish (pl-PL)
Portuguese, Brazil (pt-BR)
Portuguese, Portugal (pt-PT)
Romanian (ro-RO)
Russian (ru-RU)
Slovak (sk-SK)
Slovenian (sl-SI)
Swedish (sv-SE)
Tamil (ta-IN)
Turkish (tr-TR)
Ukrainian (uk-UA)
Urdu (ur-PK)
Sorbian (wen-DE)
Simplified Chinese, China (zh-CN)
Traditional Chinese, Hong Kong (zh-HK)

My operating system isn't listed... will you provide support for it?
My optimized build isn't listed... will you provide support for it?

I no longer provide libraries for builds that aren't hosted on or a site that provides a standard disttribution where I can download and extract the libraries for repackaging. If you know of a site that provides a distribution that you would like me to include please post a message to this affect in the MozillaZine Extensions Forum.

If you have access to a corresponding Mozilla Thunderbird build you can add the files yourself. Just find the files that are listed for your operating system in the What files are installed? section below which will be inside of the Thunderbird application's components directory, place them in the corresponding location in your Firefox application's components directory, delete the compreg.dat and xpti.dat files in your profile directory, and restart. This should force a registration of the libraries but in some cases Firefox does not register them properly and I don't have a solution for this problem.Libraries are not the same thing as a dictionary.

How do I place a button on a web page to launch SpellBound?

Not available yet... when it is instructions and samples will be available on the Web Integration page.

What about Automatic Updates?

Automatic updates are enabled for this extension. This of course only applies to releases of Firefox with a functional Extension Manager.

Where did the spell check files come?

This information is available on the Download page.

Why the name SpellBound?

Well.... obviously the word spell in the name SpellBound has something to do with it. From the early eighties onward I have been a fan of the Siouxsie and the Banshees / The Creatures and there is a song named Spellbound that she did with the Banshees.

How can I help?

Code submissions are always welcome and as for anything else I believe it is pretty well covered in the other sections already... if for what ever reason you are inclined to donate please do so to your favorite charity... I am sure they need it far more than I do but thanks for the thought.

What hidden preferences are there for SpellBound?
How do I change the spell check dialog so it isn't modal?
How do I display SpellBound in the Tools menu?

This section does not cover the preferences that can be set in the SpellBound Options dialog.

Can I change the shortcut key / keybinding to something other than ctrl/cmd+shift+f7?

This can be accomplished with the keyconfig extension. If you are wondering why I chose this combination it is due to F7 being a common key to launch a spell check but F7 on Firefox toggles caret browsing and ctrl+F7 is already used by the QuickNote extension so I settled for ctrl/cmd+shift+F7.

I get an alert stating I should re-install the libraries... what should I do?

Re-install the libraries from the Installation page.

I get an alert stating I should install a dictionary... what should I do?

Re-install your dictionaries from either the site's Installation page or the Dictionaries for Mozilla Thunderbird page. The dictionaries are installed into the components/myspell directory which is located in the application directory. When you upgrade or re-install you may have to re-install both the libraries and your dictionaries.

When I perform a spell check no misspelled words are found even though there are misspelled words... what should I do?

Install the dictionaries from either the site's Installation page or the Dictionaries for Mozilla Thunderbird page if you have not already done so. When the spell check dialog is displayed select the dictionary from the drop down box in the lower left of the dialog.

Why is an "Unable To locate Component" error displayed when I start Firefox?

If you install the incorrect spell check libraries for the version of Firefox you have installed this error is usually displayed. To fix this install the correct version of the spell check libraries for your version of Firefox. If you installed a version of the spell check libraries for a different operating system than the one you are using you should delete the files for the spell check libraries from your profile's extensions directory. The names of the files are available in the What files are installed? section.
Unable To Locate Component error

Why can't I install SpellBound from the Installation page?

Due to Bug ID 274271 the installation warning may not be displayed with Firefox Trunk builds prior to May 24th, 2005. If you have not added to your "Allowed Sites" list you will have to manually add it by going to "Tools" - "Options" - "Content" - "Allow web sites to install software" - "Allowed Sites" and adding to the "Allowed Sites" list as shown below. Firefox has a software installation "whitelist" feature where a warning may be displayed near the top of your browser window that will look similar to this.
To protect your computer, Firefox prevented this site ( from installing software on your computer.

If this warning is displayed you will need to click the "Edit Options..." button and in the dialog that is displayed (see below) add this site to the "Allowed Sites" list for installing software. After this has been completed you can start the installation process by re-visiting the Installation page.
Allowed Sites

If you are still having trouble installing SpellBound from the Installation page you should be able save the files locally by right clicking on the link and selecting "Save Link As" in Firefox or "Save Link Target As" in the Mozilla Suite. Then you should be able to drag and drop the files onto the browser window or the Extension Manager window to install them.

How do I uninstall SpellBound when using Firefox?

Open the Extension Manager (e.g. Tools - Extensions), click on SpellBound, open the context menu, and select Uninstall. Then do the same for the Extension Manager entry named "Mozilla SpellCheck Libraries". If you would also like to remove the dictionaries exit Firefox, open the components directory which is located in the same directory as the Firefox application, and delete the myspell directory.

How do I uninstall SpellBound when using the Mozilla Suite?

Open Preferences (e.g. Edit - Preferences), select SpellBound, and click the Uninstall button.

Why isn't Mozilla or Firefox or SpellBound or some other word in the dictionary?

The vast majority of the dictionaries come from OpenOffice so I have no say in the matter. It is important to note that if you check the spelling of the word OpenOffice that it is also not in the dictionaries. Also, I don't maintain the dictionaries... they are either maintained by Stefan Eskelid on the site or by the Mozilla Foundation at the Dictionaries for Mozilla Thunderbird page.

Why isn't the dictionary as complete as the dictionary for Word or Outlook?

The Trunk builds use an updated spell-checking engine that provides a much larger misspelled word suggestion list. The spellchecker used by SpellBound is for all practical purposes the same as the spellchecker used by the Mozilla Suite and Mozilla Thunderbird. These are both based on MySpell which is also used by OpenOffice and utilizes the same dictionaries as OpenOffice. If the spellchecker used by the Mozilla Suite or Mozilla Thunderbird is changed so will the spellchecker used by SpellBound and any improvements made to either of these will be added to SpellBound as well.

Why are the dictionaries no longer available directly from the install page?

There have been several reports of the download of the dictionaries from timing out and not installing as well as people not following the instructions on the Installation page for installing the dictionaries and then reporting the problem as a bug, and a couple of reports from people that have incorrect permissions on their Firefox installation that prevent them from being able to install the dictionaries. I don't maintain the dictionaries and would like to focus on extension development instead of support issues of this nature. I also never felt entirely comfortable direct linking to the dictionaries even though it made the installation much simpler. For these reasons you will have to go to the site's Installation page or the Dictionaries for Mozilla Thunderbird page to install the dictionaries.

How do I use my custom dictionary from Word, Outlook, or ieSpell?

The default custom dictionaries that these applications use is usually named CUSTOM.DIC and for Word and Outlook is located in "C:\Documents and Settings\username\Application Data\Microsoft\Proof\" and for ieSpell is located in "C:\Documents and Settings\username\Application Data\ieSpell\" (username is the username you used to log on to your OS). There is currently no way to configure the custom dictionary used by SpellBound to use these dictionaries but there is a way you can use the contents by copying either one of these custom dictionaries into your Profile Folder and renaming it to persdict.dat since the file formats are essentially the same. If there is already a persdict.dat file I suggest simply renaming it which will of course make your previous custom dictionary that was used by SpellBound unavailable.

Will you package a dictionary for me?

I no longer package dictionaries due to that most of the requests have been for dictionaries that aren't in the correct format (e.g. they must be in the same format as the MySpell dictionaries from OpenOffice)... all requests for repackaging dictionaries will simply be ignored. If you would like to repackage a dictionary yourself it is simple to do and you can use the instructions that follow to help guide you through the process.

How can I package a dictionary?

The first thing you should do is find out whether you will be violating the licenses and / or copyrights for the dictionary you are packaging.
  1. Download the English (US) dictionary from the site's Installation page. This will provide the install.js file that you can then modify for your dictionary package.
  2. Decompress (e.g. extract) it into an empty directory the dictionary package you downloaded (it is in zip format so you can use WinZip, WinRAR, or which ever compression program you prefer). You may have to rename the file extension from .xpi to .zip first for your program to recognize it.
  3. Delete all of the files that you extracted except for the install.js file.
  4. Copy your dictionary files into this directory. At minimum there should be a .dic and .aff file. There may also be a readme and / or a license file.
  5. If your dictionary has a locale (e.g. en-US where US is the locale) then the locale should be separated with a -. It is important to note that dictionaries from OpenOffice use _ as a separator
  6. Open the install.js file in a text editor and modify the following:
    • const APP_DISPLAY_NAME = "English (US) dictionary"; change English (US) to the name and if applicable locale for your dictionary.
    • const APP_NAME = "spell-en-US"; change en-US to the language and if applicable the locale of your dictionary.
    • const APP_PACKAGE = ""; change to the location where your dictionary will be located on the internet (not required). I highly recommend submitting your dictionary to if others would find it useful.
    • const APP_VERSION = "0.2"; change 0.2 or what ever version number is present to reflect the version number of your dictionary. If this is the first time a dictionary for this language has been made available to Mozilla it should be 0.1.
    • addFile(APP_NAME, "en-US.dic", myspell_folder, ""); change en-US.dic to the name of your dictionary's .dic file.
    • addFile(APP_NAME, "en-US.aff", myspell_folder, ""); change en-US.aff to the name of your dictionary's .aff file.
    • addFile(APP_NAME, "README-en-US.txt", myspell_folder, ""); change README-en-US.txt to the name of your dictionary's readme file. If you don't have a readme file this line can just be deleted. If you also have a separate license file you can copy this line and change it to reference your license file.
  7. Compress the files using zip compression (the file's extension must be .xpi), install the dictionary, and see if it works.

What files are installed?

Additional information regarding the files is available on the Download page. Both Firefox and the Mozilla Suite require the SpellBound extension (e.g. spellbound_x.x.x.xpi) to be installed but Firefox requires two additional xpi files to be installed. The first file contains the Mozilla spell check libraries (e.g. spellbound_lib_os_name-x.x.x.xpi) and the second file contains the dictionary files and are available from the site's Installation page or Dictionaries for Mozilla Thunderbird page. Below I have listed what is installed by the spellbound_lib files for each OS when using Firefox. The files have been packaged with the following permissions... 0755 for the libraries (e.g. /, etc.) and 0644 for all of the remaining files (e.g. spellchecker.xpt) to get around Bug ID 189905 which primarily affects Linux and FreeBSD users.

All Operating Systems (e.g. Windows, Linux, Mac OS X, OS/2, and FreeBSD) Windows and OS/2 Linux Mac OS X FreeBSD
Copyright © 2004-2005 Robert Strong All rights reserved
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