User:T burnout

var addExtraButtons = function(){

   mw.toolbar.addButton( {
       imageFile: 'http://upload.wikimedia.org/wikipedia/en/1/12/Button_gallery.png',
       speedTip: 'Comment visible only for editors',
       tagOpen: ,
       sampleText: 'Insert comment here',
       imageId: 'button-comment'
   } );

};

if( $.inArray( mw.config.get( 'wgAction' ), [ 'edit', 'submit' ] ) !== -1 ) {

   mw.loader.using( 'user.options', function () {
       if ( ! mw.user.options.get( 'usebetatoolbar' ) ) {
           mw.loader.using( 'mediawiki.action.edit', function(){
               $( addExtraButtons );
           } );
       }
   } );

}