The end result has to be some combination of HTML, CSS, and JavaScript; otherwise, your browser really won’t know what to do. Now, here’s where the special nature of React comes in.

The two key things to notice in the screenshot are the ReactDOM.render() call in the JavaScript at the right, which puts its output into the 'root' element, and the "root" div in the HTML at left.

MDN Web Docs is an excellent example of a Free and Open-Source (FOSS) platform. You can access HTML, CSS, and JavaScript documentation and examples on a well-organized website. Among the tools the ...