Although it is not always the true specially with some of the more advanced interactions we have in CSS in modern browsers. However, JS is most commonly used for front end development. It means that any kind of programing that happens in any web browser, be it Google Chrome, Mozilla Firefox, or Opera.
But increasingly, you will also see that Java Script is used in back-end development through technologies such as “.js” and the like. Hence, JS is used for any kind of programming on the web.
Some Examples for the Use of JS