Defines HTML on the top of the sidebar. If you set topHTML property it will appear on the top of the sidebar. The property will accept any HTML or text string and will stay on top even if sidebar has a scroller. You can define it during object creation: let sidebar = new w2sidebar({ name : 'sidebar', topHTML: 'some text', nodes: [ { id: 'id-1', text: 'Level 1' }, { id: 'id-2', text: 'Level 2' }, { id: 'id-3', text: 'Level 3' } ] }); Or any time after the object has been created: w2ui.sidebar.topHTML = 'some text'; w2ui.sidebar.refresh();