Many people already know that the code that makes up a website or app is written in one of two programming languages: HTML and CSS (HyperText Markup Language and Cascading Style Sheets) for web pages and JavaScript for apps. But what does it all mean? What's the difference between those two languages, and how do they work together to make an application?

It can be difficult for beginners to understand what JavaScript is used for, let alone learn about its broader applications. This guide is designed to give you a brief overview of the many uses of JavaScript as well as introduce you to some basic terminology with which you might not be familiar. You can also check out our JavaScript tutorial to learn more.