This website contains links to software which is either no longer maintained or will be supported only until the end of 2019 (CKFinder 2). For the latest documentation about current CKSource projects, including software like CKEditor 4/CKEditor 5, CKFinder 3, Cloud Services, Letters, Accessibility Checker, please visit the new documentation website.

If you look for an information about very old versions of CKEditor, FCKeditor and CKFinder check also the CKEditor forum, which was closed in 2015. If not, please head to StackOverflow for support.

Frequently Asked Questions

In this page you can find Frequently Asked Questions (and answers) about FCKeditor. Please do not use this page just for asking questions. For support and discussion questions I invite you to go to our Forums.

Can I use FCKeditor in my commercial software? Must my software be Open Source too?

The editor is licensed under the GPL, LGPL and MPL Open Source licenses making it possible to use it with almost all kinds of software. If these Open Source licenses terms satisfy your needs, you can freely use FCKeditor in your commercial software. You may use any GPL, LGPL or MPL compatible license you want for your software, and it is not mandatory for it to be Open Source or Free Software, except for the GPL license. Just be sure you are properly satisfying all license terms.

Even if it is free to use FCKeditor, consider giving something back to the project, mainly when using it on commercial software. In this way you can help us maintain the project and the high quality of the editor. It is also the only way for us to compete with commercial editors. Take a look at our commercial license for some options.

For many companies and products, Open Source licenses are not an option. This is why the Closed Distribution License has been introduced: http://www.fckeditor.net/license

What about the "FCKeditor" name?

The editor name starts with the initials of its author, Frederico Caldeira Knabben (see Acronym Finder). It must be written with the "FCK" initials in uppercase, concatenated with the "editor" word in lowercase, with no spaces between them. It is pronounced as you "should" read it: "eff see kay editor".

For version 3, FCKeditor is changing name to CKEditor.

Do I have to show the original about box in the toolbar?

No. There is no problem on removing the About button from the toolbar. You don't need to show the editor name to your end users at all.

In any case, the legal notices in the editor sources must remain untouched.

In the file browser, I'm having a "XML Request Error : Internal Server Error (500)" . How to find out the problem?

The editor uses a "connector" in the file browser to communicate with the server, through XML, and retrieve files and folders. The connector is available in different programming languages, as ASP and PHP for example.

By default, it is configured to use the ASP one. Be sure you have configured the editor to use the appropriate connector for your preferred language. You can do that in the fckconfig.js file or in your custom Configuration File.

If the configurations seem to be OK, you can use the test page that comes with the connector to check the XML responses that the connector sends and maybe identify errors on the server side. The test page for version before 2.5 is located at "editor/filemanager/browser/default/connectors/test.html". In 2.5 the location has been moved to "editor/filemanager/connectors/test.html"

Another thing to check is that the target folder for the files exists in your server. By default it uses the "/UserFiles/" folder, but it is configurable.

The editor uses a fixed structure in the target folder that separate files used on different dialog boxes, respectively the link, file and flash dialogs. For example, if you are using the "/UserFiles/" as your target file, it will use "/UserFiles/File/", "/UserFiles/Image/", "/UserFiles/Flash/" and "/UserFiles/Media/". The connector tries to create those directories automatically, but on some configurations they need to be created manually to make it work properly.

NOTE for ASP connector: another workaround seem to re-install VBScript runtime (from http://msdn.microsoft.com/scripting) and/or MDAC (from http://msdn.microsoft.com/data/mdac/). Ultimate way : register the scripting library with running "regsvr32 vbscript.dll" in the "<windows folder>\system32\" folder. Also, if IIS is configured to allow "Anonymous" acces, ensure that the IUSR_MACHINENAME account has write permissions to the folder(s).

NOTE for PHP connector: some others problems can generate XML HTTP request error.

Why am I getting "Permission denied" errors when I'm opening the FCKeditor HTML samples in Firefox 3 from the local filesystem?

Firefox 3 has implemented a "strict origin policy" on local files which limits the scope of files accessible from an HTML document opened form the local filesystem. When a local HTML document opens another HTML document in an iframe from the local filesystem which is outside of Firefox 3's same origin scope, and the child iframe document attempts to access JavaScript variables in the parent document, Firefox 3 will treat the JavaScript access as XSS (cross site scripting) and will give out a permission denied error. There is currently no way to fix this from within FCKeditor's code short of changing the directory structure of FCKeditor's package.

The problem can be fixed at the browser by disabling the security check, however. Disabling the new Firefox 3 security check will only affect HTML documents opened form the local filesystem and not those opened from the Internet and thus it shouldn't pose any significant security risk for most people. The security check can be disabled with the following steps:

  1. Point Firefox 3 to about:blank
  2. Look for the configuration directive security.fileuri.strict_origin_policy
  3. Set security.fileuri.strict_origin_policy to false by double clicking on it

After disabling the security check, FCKeditor on the local filesystem should work in Firefox 3.