CKSource

CKEditor comes with a rich set of configuration options that make it possible to customize its appearance, features, and behavior. The main configuration file is named config.js. This file can be found in the root of the CKEditor installation folder.

Available Configuration Options

All available configuration options can be found in the CKEditor JavaScript API documentation. Refer to the CKEDITOR.config object definition.

Defining Configuration In-Page

The best way to set the CKEditor configuration is in-page, when creating editor instances. This method lets you avoid modifying the original distribution files in the CKEditor installation folder, making the upgrade task easier.

In-page settings can be passed to any of the editor instance creation functions, namely CKEDITOR.replace and CKEDITOR.appendTo. For example:

CKEDITOR.replace( 'editor1',
    {
        toolbar : 'Basic',
        uiColor : '#9AB8F3'
    });

Note that the configuration options are passed through a literal object definition (starting with a "{" symbol and ending with a "}" symbol). Because of this the proper syntax for each option is (configuration name) : (configuration value). Be sure to not use the "equal" character (=) in place of the colon character (:).

Using the config.js File

CKEditor settings can also be configured by using the config.js file. By default this file is mostly empty. To change CKEditor configuration, add the settings that you want to modify to the config.js file. For example:

CKEDITOR.editorConfig = function( config )
{
    config.language = 'fr';
    config.uiColor = '#AADC6E';
};

The above CKEDITOR.editorConfig function definition must always be defined so that the settings could be applied. The config.js file will be executed in the scope of your page, so you can also make references to variables defined in-page or even in other JavaScript files.

Using a Custom Configuration File

Using a custom configuration file is another recommended method of setting CKEditor configuration. Instead of using the default config.js file, you can create a copy of that file anywhere in your website and simply point the editor instances to load it. The advantage of this approach is that in this way you can avoid changing the original file, which makes it easier to upgrade CKEditor later by simply overwriting all files.

Suppose you will have copied the config.js file to a folder named custom in the root of your website. You will also have renamed the file to ckeditor_config.js. At that point it is enough to only set the customConfig configuration option when creating the editor instances. For example:

CKEDITOR.replace( 'editor1',
    {
        customConfig : '/custom/ckeditor_config.js'
    });

The custom configuration file must look just like the default config.js file.

Configurations Overload Order

You're not required to use only one of the above configuration options. You can mix all of them, and the configurations will be overloaded properly. The following is configurations loading order when creating an editor instance:

1. The editor instance is created. At this point all its default configurations are set.
2. If the customConfig setting has been set "in-page", that file is loaded, otherwise the default config.js file is loaded. All settings in this file override the current instance settings.
3. If the settings loaded in point "2" also define a new customConfig value, this new file is loaded and its settings overload the current instance settings. This happens recursively for all files until no customConfig is defined.
4. Finally the settings defined "in-page" override the current instance settings (except customConfig, which has been used at point "1").

Avoiding Loading External Settings Files

It is also possible to completely avoid loading an external configuration file, reducing the number of files loaded. To do that, it's enough to set the customConfig setting to an empty string. For example:

CKEDITOR.replace( 'editor1',
    {
        customConfig : ''
    });

This setting is definitely recommended if you are not setting configurations in the config.js file nor a custom configuration file.