Web Browser Engineering

This is the source code to Web Browser Engineering, my book on how web browsers work. The best way to read the book is online.

Building the book

If you want to build from source, run:

make book draft blog

The source code contains:

• The Markdown source for the book text, in book/
• A template and code for converting the book to HTML, in infra/
• Chapter-by-chapter implementations of the browser, in src/
• Styling for the book's website, in www/
• The Python backend for the book's former feedback system, in www/ and infra/.

The book's built-in feedback system is disabled. Please open a GitHub issue with typos or small comments about the text.

You can run the book's built-in checks with:

make lint

We're always happy to hear from readers and from educators who want to use the book. Please email us!

Running the browser

Code for the browser developed in the book can be found in src/, in files named lab1.py, lab2.py, and so on, corresponding to each chapter.

To run it, you'll need to install:

• A recent Python 3; version 3.9.10is known to work, but older versions probably will too.
• The tkinter package, part of the Python standard library but often isn't included in pre-installed Pythons on macOS and Linux. You can check by running python3 -m tkinter, which should open a test window.
• For Chapter 9+, the dukpy package. Consult that chapter for installation instructions.
• For Chapter 11+, the skia and pysdl2 packages. Consult that chapter for installation instructions.

Once you have the above, you can run, say, the browser as of the end of Chapter 3 like so:

cd src/
python3 lab3.py https://browser.engineering

Every chapter can be run in a similar fashion.

For chapters 8 onward, there's also a "guest book" web application, which you can run with:

cd src/
python3 server8.py

Like the browser, there are different versions of the server for different chapters, named server8.py, server9.py, and so on.

You can also run the book's unit tests with:

make test

Rebuilding the quiz JavaScript

The source for the interactive multiple-choice quizzes is taken from mdbook-quiz. To rebuild the JS blob that we include on the quiz pages (located in www/quiz-embed.iife.js) do the following:

• Install depot (made by the same people who made mdbook-quiz; tldr: cargo install depot-js --locked).
• Ensure you have cargo-make installed.
• git clone https://github.com/cognitive-engineering-lab/mdbook-quiz && cd mdbook-quiz
• cargo make init-bindings
• cd js
• depot build

The quiz-embed.iife.js file should be in packages/quiz-embed/dist/.

These instructions are taken from the README.md and CONTRIBUTING.md files in the mdbook-quiz project.