If you've ever clicked a button on a website and something happened — a popup appeared, an image changed, or a form got submitted — that was JavaScript doing its job.

JavaScript is everywhere. And if you want to build anything on the web, you need to understand it.

In this article, I'll explain what JavaScript is, what it does, and why it should be the next skill you learn.

What Exactly is JavaScript?

When you build a website, you use three main technologies: