JavaScript is a programming language that makes it possible to implement complex web page behavior. Every time you see a web page, it not only displays static content, but also does more - displays content updates in a timely manner, displays interactive maps, 2D / 3D animations, scrolls videos, etc. - Rest assured, JavaScript is involved.
The most famous use of JavaScript is, of course, web development. Most often, JS is used when you need to add dynamism to the site or make a browser application, but if you wish, you can write a backend on it.

JavaScript is different:

prototypical programming style (instead of classes and inheritance - prototypes and cloning);
weak dynamic typing;
functions as first-class objects (that is, they can be created right at runtime).
If you need JavaScript Development services but do not understand anything about this, then you can turn to https://scand.com/technologies/javascript/ for help, which will definitely help you with this!
JavaScript is used for PWA development. For example, sites built with the Gatsby js generator support the functionality of a progressive web app out of the box. This is another plus in favor of the demand for JS in the near future.