MediaWiki:Common.js

var customizeToolbar = function() {

$( '#wpTextbox1' ).wikiEditor( 'addToToolbar', {
        section: 'main',
        group: 'format',
        tools: {
                "hline": {
                        label: 'Horizontal line',
                        type: 'button',
                        icon: '//bits.wikimedia.org/skins-1.5/common/images/button_hr.png',
                        action: {
                                type: 'encapsulate',
                                options: {
                                        pre: "----",
                                        ownline: true
                                }
                        }
                }
        }
} );
        /* Your code goes here */

};
 
/* Check if we are in edit mode and the required modules are available and then customize the toolbar */
if ( $.inArray( mw.config.get( 'wgAction' ), ['edit', 'submit'] ) !== -1 ) {
        mw.loader.using( 'user.options', function () {
                if ( mw.user.options.get('usebetatoolbar') ) {
                        mw.loader.using( 'ext.wikiEditor.toolbar', function () {
                                $(document).ready( customizeToolbar );
                        } );
                }
        } );
}