Now if you've never heard of JavaScript before, that's perfectly fine. JavaScript is a programming language, and it's not just a regular one. It's actually the most popular programming language in the world today, and there are some key reasons for that, and that's what we're going to walk through in this video.

Just about every website and application in the world today uses JavaScript in some form or another, and the key reason why that is, is because JavaScript is the only programming language that can be interpreted in the browser.

So what does that mean exactly? Well, every other programming language, like Java - and don't get Java and JavaScript confused. They're not related whatsoever, but Java, Ruby, Python, any other programming language out there needs to have a certain type of configuration items, and it needs to be processed on a server.

JavaScript is very different. JavaScript was created several decades ago, and it was created with the goal that it could actually be processed directly by a web browser, and so that is why it's so popular because it doesn't need a special server in order to run.

If someone accesses a website with JavaScript on it, the JavaScript is actually able to process requests and to perform things like calculations or to do things like show and hide content, and it can do it incredibly fast because it doesn't have to go back and communicate with a server.

When I started programming around 15 or so years ago, JavaScript was still pretty young, and most developers simply used it to add some nice look and feel elements to their website, so I remember using JavaScript to toggle content, so you might click a button, and content would show up, and then it would hide. And you would usually use JavaScript for things like that.

But because JavaScript can be rendered directly in the browser, it has become incredibly popular. And now with frameworks like Vue and React, you can actually build entire applications that the browser is able to process, and you're able to build incredibly dynamic and reactive applications.

In addition to that, because JavaScript is so flexible, you now have the ability to build native mobile applications, so many times you might be using an iOS or an Android application, and you may not even realize that you're actually using an application that was built completely in JavaScript.