CKSource

CKEditor offers a powerful and flexible output formatting system. It gives developers full control over what the HTML code produced by the editor will look like. The system makes it possible to control all HTML tags and can give a different result for each one of them.

The HTML Writer

Technically speaking, writing the final output is a task executed by the CKEDITOR.htmlWriter class ("writer"), used by the CKEDITOR.htmlDataProcessor class. Therefore, the current writer instance for a specific editor instance can be retrieved by the editorInstance.dataProcessor.writer property.

It is possible to configure several output formatting options by setting the writer properties. The following example summarizes the most used of them, giving their default values:

var writer = editor.dataProcessor.writer;

// The character sequence to use for every indentation step.
writer.indentationChars = '\t';

// The way to close self closing tags, like <br />.
writer.selfClosingEnd = ' />';

// The character sequence to be used for line breaks.
writer.lineBreakChars = '\n';

// The writing rules for the <p> tag.
writer.setRules( 'p',
    {
        // Indicates that this tag causes indentation on line breaks inside of it.
        indent : true,

        // Inserts a line break before the <p> opening tag.
        breakBeforeOpen : true,

        // Inserts a line break after the <p> opening tag.
        breakAfterOpen : true,

        // Inserts a line break before the </p> closing tag.
        breakBeforeClose : false,

        // Inserts a line break after the </p> closing tag.
        breakAfterClose : true
    });

Setting Writer Rules

Because the writer is a property of each editor instance, and also due to its dependency on the writer plugin to be loaded, the best way to modify it is by listening to the instanceReady event, so it is safe to assume that the dataProcessor property will be loaded and ready for changes. The following code shows an example of this approach used when creating an editor instance:

CKEDITOR.replace( 'editor1',
    {
        on :
        {
            instanceReady : function( ev )
            {
                // Output paragraphs as <p>Text</p>.
                this.dataProcessor.writer.setRules( 'p',
                    {
                        indent : false,
                        breakBeforeOpen : true,
                        breakAfterOpen : false,
                        breakBeforeClose : false,
                        breakAfterClose : true
                    });
            }
        }
    });

Another method is to use the CKEDITOR object, so all editor instances will be changed:

CKEDITOR.on( 'instanceReady', function( ev )
    {
        // Ends self closing tags the HTML4 way, like <br>.
        ev.editor.dataProcessor.writer.selfClosingEnd = '>';
    });