In this chapter, we’ll explore the data structure Map (a class) which lets us translate (“map”) from an input value to an output value. We’ll use a Map to display text upside-down in a terminal!

In this chapter, we explore the popular data format JSON. And we implement shell commands via Node.js that read and write files.

In this chapter, we learn how to handle tasks that take a long time to complete – think downloading a file. The mechanisms for doing that, Promises and async functions are an important foundation of JavaScript and enable us to do a variety of interesting…

In this chapter we develop a small web app in the same way that large professional web apps are developed: We use libraries that we install via npm. We write tests for some of the functionality. We combine all JavaScript code into a single file before we…

In this chapter, we’ll take a look at frontend frameworks – libraries that help with programming web user interfaces (“frontend” means “browser”, “backend” means “server”). We’ll use the frontend framework Preact to implement the frontend part of a todo list…

In this chapter, we’ll write our own web server: It will serve files and manage the data for a browser app.

In this chapter, we learn how to write a server that lets users log in via passwords. That process is called authentication.

In this chapter, we install a package manager for our operating system. That enables us to install shell commands that we can’t get via npm.

In this chapter, we explore Markdown, a lightweight markup language that’s easy to learn and used a lot when writing about programming: documentation, comments, etc. We’ll need it in the next chapter. Learning it may seem like a detour but it’s easy to pick…

In this chapter, we learn how to use the version control system Git and a useful companion website, GitHub. Both are important tools when programming in teams but even help programmers who work on their own.

WebAssembly (abbreviated Wasm) is a binary instruction format for a stack-based virtual machine. Wasm is designed as a portable compilation target for programming languages, enabling deployment on the web for client and server applications.

Browserslist has added support for Baseline queries. Find out what that could mean for your developer workflow.

Read about various happenings with Baseline during August 2025.

Join the AMA on r/webdev on September 18 and ask us anything!

Our popular Learn CSS course has been updated with new modules covering the latest CSS features.

Find out about the progress of Interop 2025, and how to submit your ideas for 2026.

Want to make the web better for a chance to win cash prizes? Join the Baseline Tooling Hackathon!

Discover some of the interesting features that have landed in stable and beta web browsers during August 2025.

At Chrome, we want to know what your Baseline target is—and here's how you can help!

In this chapter, we learn how to create web pages via HTML.

In this chapter, we perform a few steps to prepare us for web development.