What JavaScript Is? If you’re new to programming, you’ve probably heard of a programming language called Java. And you are learning JavaScript is an entirely different language. JavaScript is the most popular client-side scripting language at the moment, where the client-side means that all of the code gets executed on the client’s or the user’s computer. The user computer sends through a request to the server, and then the server sends a response back to your computer, so there are two different types of scripting languages: client-side scripting language like JavaScript, and server-side scripting languages like PHP and Django.