The DOM element where to render the object. Usually it is a DIV, but can be any block element. If you change .box property you will need to call .render() method to render widget inside the new DOM element. If you specify a selector, there is no need to define .box because it will be automatically set. let layout = new w2layout({ name : 'layout', panels : [ { type: 'top', size: 40 }, { type: 'preview', size: 200 } ] }); The layout is created in memory. You can render it in one of the following ways: $('#layout').w2render('layout'); // preferred way or w2ui.layout.render($('#layout')[0]); or w2ui.layout.box = $('#layout')[0]; w2ui.layout.render();