MediaWiki:Common.js

/* Any JavaScript here will be loaded for all users on every page load. */

var customizeToolbar = function () {
	/* Your code goes here */
$( '#wpTextbox1' ).wikiEditor( 'addToToolbar', {
	'section': 'Advanced',
	'groups': {
		'MCQs': {
			'label': 'MCQs' // or use labelMsg for a localized label, see above
		}
	}
} );

}

/* Check if view is in edit mode and that the required modules are available. Then, customize the toolbar … */
if ( [ 'edit', 'submit' ].indexOf( mw.config.get( 'wgAction' ) ) !== -1 ) {
	mw.loader.using( 'user.options' ).then( function () {
		// This can be the string "0" if the user disabled the preference ([[phab:T54542#555387]])
		if ( mw.user.options.get( 'usebetatoolbar' ) == 1 ) {
			$.when(
				mw.loader.using( 'ext.wikiEditor' ), $.ready
			).then( customizeToolbar );
		}
	} );
}