What is JavaScript?
JavaScript is a powerful programming language that can add interactivity to a website. It was invented by Brendan Eich.
JavaScript is versatile and beginner-friendly. With more experience, you’ll be able to create games, animated 2D and 3D graphics, comprehensive database-driven apps, and much more!
JavaScript itself is relatively compact, yet very flexible. Developers have written a variety of tools on top of the core JavaScript language, unlocking a vast amount of functionality with minimum effort. These include:
- Browser Application Programming Interfaces (APIs) built into web browsers, providing functionality such as dynamically creating HTML and setting CSS styles, collecting and manipulating a video stream from a user’s webcam, or generating 3D graphics and audio samples.
- Third-party APIs that allow developers to incorporate functionality in sites from other content providers, such as YouTube or Facebook.
- Third-party frameworks and libraries that you can apply to HTML to accelerate the work of building sites and applications.
It’s outside the scope of this article—as a light introduction to JavaScript—to present the details of how the core JavaScript language is different from the tools listed above. You can learn more in our Core modules, as well as in other parts of MDN.
The section below introduces some aspects of the core language and offers an opportunity to play with a few browser API features too. Have fun!
A “Hello world!” example
JavaScript is one of the most popular modern web technologies! As your JavaScript skills grow, your websites will enter a new dimension of power and creativity.
However, getting comfortable with JavaScript is more challenging than getting comfortable with HTML and CSS. You should start small, and progress gradually. To begin, let’s examine how to add JavaScript to your page for creating a Hello world! example.