This example shows how to create accordion menu using bootstrap framework.
Firstly, you should add the following code to the head section in html:
HTML or HyperText Markup Language is the standard markup language used to create web pages.
Cascading Style Sheets (CSS) is a style sheet language used for describing the look and formatting of a document written in a markup language.
Bootstrap is the most popular HTML, CSS, and JS framework for developing responsive, mobile first projects on the web.