In the Bootstrap4 vertical menu known as a sidebar. In this case, the element does not have a .navbar class, so we set it as the data target by referring to an id of this element. For example, display a form as the “Subscribe” button is pressed, otherwise, form is not visible. The well-crafted templates give users access to a wide range of components and elements that are essential to build a powerful web application. The navigation header, or the navbar, should be created using the tag or a tag with the role=”navigation” attribute. Bootstrap transparent navbar looks good in both desktop computers and mobile devices. Drop Down Navigation Menu. Bootstrap 4 menu kit Tutorials, code snippets, CSS library.