HTML & CSS Core

Yes

Browsers understand HTML through a rendering engine that parses the HTML document, constructs a Document Object Model (DOM) tree, and renders it visually on the screen.

Some browser engines are open source, while others are not. For example:

• Open Source Engines:

  • Blink (used by Chrome and Chromium-based browsers)
  • WebKit (used by Safari)

• Closed Source Engines:

  • Gecko (used by Firefox) is mostly open-source, but some parts may not be.
  • EdgeHTML (legacy Microsoft Edge engine) was closed-source.

Most modern browsers rely on open-source engines to foster collaboration and innovation.

You can find Blink, the rendering engine used by Chromium-based browsers (like Google Chrome), in the open-source Chromium project. The source code is available at:

Chromium Git Repository

To explore Blink specifically, you can navigate to its subdirectory within the Chromium project:

Blink Source Code

This repository includes all the necessary code and documentation for Blink.

The output of this plugin was redacted.

Apologies for the earlier confusion. The links I provided were incorrect. You can access Blink's source code through the Chromium project. The correct URL is:

- Chromium Git Repository

Within this repository, Blink's source code is located in the third_party/blink/ directory.

For more information about Blink, you can visit the Blink documentation.

These resources provide access to Blink's source code and related documentation.

Blink is an open-source browser rendering engine developed by Google as part of the Chromium project. It is responsible for interpreting and rendering HTML, CSS, and JavaScript to display web pages in a browser.

Key Features and Responsibilities of Blink:

1. HTML Parsing and DOM Construction: Blink parses HTML documents to construct the DOM (Document Object Model), a tree-like structure representing the webpage's content and structure.

2. CSS Parsing and Style Calculation: It parses CSS files and inline styles, calculating how elements should be styled, including colors, sizes, fonts, and layout rules.

3. Layout and Rendering: Blink determines the layout of each DOM element and renders it to the screen, handling tasks like text placement, images, and animations.

4. JavaScript Execution: While JavaScript execution is primarily handled by V8, Google’s JavaScript engine, Blink collaborates closely with it to handle DOM manipulations and browser-specific APIs.

5. Support for Web Standards: Blink implements web standards defined by organizations like the W3C (World Wide Web Consortium) and WHATWG (Web Hypertext Application Technology Working Group), ensuring interoperability across browsers.

History of Blink:

• Forked from WebKit: Blink was forked from the WebKit engine in 2013. WebKit was originally developed by Apple and used in Safari. Google decided to create Blink to innovate faster and address architectural concerns specific to Chromium-based browsers.

• Part of Chromium: Blink is integral to Chromium, the open-source project behind Google Chrome, Microsoft Edge, Opera, and other Chromium-based browsers.

Supported Browsers:

Blink powers several modern web browsers, including:

• Google Chrome
• Microsoft Edge (Chromium version)
• Opera
• Brave
• Vivaldi

Contributions and Open-Source Nature:

• Blink is open-source, hosted as part of the Chromium project, and contributions from developers worldwide are welcome.
• Its source code can be found in the Chromium repository.

Blink is designed to be highly performant, focusing on speed, efficiency, and adherence to modern web standards, making it one of the most widely used rendering engines in the world.

Creating a browser engine is a complex task that requires knowledge in multiple domains like parsing, rendering, graphics, and networking. While there aren't many books specifically focused on "how to create a browser engine," there are resources that cover the foundational technologies and concepts you'll need. Here are some recommendations:

Books on Core Concepts

1. Parsing and Compilers:

   • "Compilers: Principles, Techniques, and Tools" by Alfred V. Aho, Monica S. Lam, Ravi Sethi, and Jeffrey D. Ullman (The "Dragon Book").
   • "Modern Compiler Implementation in C/Java" by Andrew W. Appel.

2. Rendering and Graphics:

   • "Computer Graphics: Principles and Practice" by John F. Hughes, Andries van Dam, et al.
   • "Real-Time Rendering" by Tomas Akenine-Möller, Eric Haines, and Naty Hoffman.

3. Web Standards and Specifications:

   • "Web Performance in Action" by Jeremy L. Wagner.
   • W3C and WHATWG specifications (HTML Standard, CSS Specifications, etc.).

4. Operating Systems and Networking:

   • "Modern Operating Systems" by Andrew S. Tanenbaum.
   • "Computer Networking: A Top-Down Approach" by James F. Kurose and Keith W. Ross.

Online Tutorials and Resources

1. Creating a Browser from Scratch:

   • Build Your Own Web Browser by Matt Brubeck. This is a series of blog posts walking through the creation of a simple browser engine.

2. Open-Source Browser Projects:

   • Study the source code of open-source browsers like Chromium, Servo (Mozilla's experimental engine), or WebKit. These provide real-world implementations of browser engines.

3. Browser Engineering Course:

   • Browser Engineering by Anthon Pang. This is an online textbook that provides a step-by-step guide to building a toy browser engine.

4. Graphics Programming Tutorials:

   • Learn OpenGL for understanding rendering techniques that are often used in browser engines.

Hands-On Practice

1. Start with a Toy Engine:

   • Use tutorials like Matt Brubeck's or Browser Engineering to build a simplified version of a browser engine.

2. Contribute to Open Source:

   • Join projects like Chromium, Servo, or WebKit to gain firsthand experience working on a browser engine.

3. Build Incrementally:

   • Start by creating a simple HTML parser.
   • Add CSS parsing and layout calculations.
   • Integrate JavaScript using an existing engine like V8 or SpiderMonkey.

Communities and Forums

• Web Standards Groups: Participate in W3C or WHATWG discussions.
• GitHub/Reddit: Communities like r/programming and browser engine project repositories.

With these resources, you can progressively develop the skills and knowledge to build a browser engine. Start small, and as you gain more understanding, tackle the more complex components.

Browser engines are typically developed using low-level, high-performance languages that allow fine-grained control over memory and CPU usage, as performance is a critical aspect of their functionality. Here are the most commonly used languages in browser engine development:

Main Languages

1. C++:

   • Widely used in most browser engines due to its performance, portability, and control over system resources.
   • Examples:
     • Blink (Chromium-based browsers like Google Chrome)
     • WebKit (Safari)
     • Gecko (Firefox)

2. Rust:

   • Gaining popularity for its memory safety features without sacrificing performance.
   • Example:
     • Servo (Mozilla's experimental browser engine, a precursor to some Rust features used in Gecko)

3. C:

   • Used for low-level components and performance-critical parts of some engines.
   • Example:
     • Older parts of WebKit and other legacy components.

Supporting Languages

1. JavaScript:

   • Used for testing, automation, and as the core scripting language interpreted by the engine.

2. Python:

   • Often used in build systems, testing frameworks, and scripts for tasks like code generation.

3. Objective-C/Swift:

   • For integrating browser engines with macOS and iOS applications (e.g., WebKit in Safari).

4. Java:

   • Used in Android's WebView and Chromium implementations for mobile browsers.

5. TypeScript/HTML/CSS:

   • For testing, UI prototyping, and user interface layers, especially in open-source projects.

Language Usage by Engine

Why These Languages?

• C++: Provides high performance, portability, and mature libraries for graphics and networking.
• Rust: Offers memory safety without a garbage collector, reducing security vulnerabilities like buffer overflows.
• C: Efficient for low-level tasks like networking and graphics integration.
• Scripting Languages: Facilitate rapid testing, automation, and tooling.

The choice of language depends on the goals of the engine, with C++ and Rust leading due to their balance of performance and control.

Browsers understand and process CSS through a series of steps as part of their rendering pipeline. Here’s a breakdown of how browsers handle CSS:

1. Parsing CSS

• Browsers parse CSS into a Stylesheet Object Model (CSSOM), which is similar to the DOM for HTML.
• The CSS text (either inline, in <style> tags, or external stylesheets) is tokenized and transformed into a tree structure of rules and properties.

Example:
For the CSS:

body {
  background-color: lightblue;
}
h1 {
  color: darkblue;
}

The browser creates a CSSOM tree:

Stylesheet
├── body
│   └── background-color: lightblue
└── h1
    └── color: darkblue

2. Matching CSS Selectors

• The browser matches CSS selectors (e.g., body, h1, .class, #id) against elements in the DOM.
• The matched rules are applied based on specificity (inline styles > IDs > classes > element selectors) and cascading order (later rules overwrite earlier ones if they target the same element).

3. Combining DOM and CSSOM

• The browser combines the DOM (from HTML) and CSSOM (from CSS) into a Render Tree.
• The render tree contains only the visible elements and their computed styles (including dimensions, colors, etc.).

4. Style Calculation

• The browser calculates the final styles for each element, considering:
  • Inheritance: Some properties (e.g., color, font-family) are inherited by default, while others (e.g., margin, border) are not.
  • Default styles: If no CSS rule is provided, the browser applies its user agent stylesheet (built-in default styles).

5. Layout and Painting

• Layout: The browser calculates the size and position of each element in the render tree.
• Painting: Styles (e.g., background color, borders, text color) are painted onto the screen.

Tools to Explore CSS Processing

• Use browser developer tools (e.g., Chrome DevTools, Firefox Developer Tools) to inspect:
  • The Computed Styles tab: Shows the final styles applied to an element.
  • The Rules tab: Displays the source of the applied CSS rules.

Behind the Scenes: Engine's Role

• Parsing: Handled by the browser engine’s CSS parser.
• Selector Matching: Algorithms efficiently match selectors to elements.
• Rendering: The rendering engine (e.g., Blink, Gecko) applies styles during the rendering process.

This process ensures that browsers accurately interpret CSS rules and render web pages as intended.

The browser engine handles CSS as part of its overall rendering pipeline. There isn’t a separate engine solely for CSS; instead, CSS processing is a specialized subsystem within the browser engine. Here’s how this integration works:

Components of a Browser Engine

A browser engine like Blink, WebKit, or Gecko is divided into multiple subsystems, each responsible for a part of the rendering process. These include:

1. HTML Parser: Handles HTML and constructs the DOM.
2. CSS Parser: Processes CSS and constructs the CSSOM.
3. JavaScript Engine: Executes JavaScript code and manipulates the DOM and CSSOM.
4. Layout Engine: Combines DOM and CSSOM into a render tree and calculates element positions.
5. Painting and Compositing Engine: Draws the styled elements on the screen.

CSS Handling as Part of the Browser Engine

• The CSS subsystem is responsible for parsing and applying CSS rules.
• It integrates tightly with other subsystems like:
  • The DOM to apply styles to elements.
  • The layout and painting engine to calculate visual representation and render the page.

How CSS Integrates

1. Parsing CSS: The browser engine's CSS parser turns raw CSS into a CSSOM.
2. Selector Matching: The CSS subsystem matches styles to DOM elements.
3. Style Computation: The CSS subsystem calculates the final style for each element.
4. Interaction with JavaScript: JavaScript can dynamically modify CSS or DOM elements, and the CSS subsystem recalculates styles as needed.

Specialized Libraries within Engines

While the CSS subsystem is part of the browser engine, it often uses modular components:

• Style Resolver: Determines which rules apply to which elements.
• Layout Manager: Calculates positions and sizes based on styles.
• Graphics Library: Handles visual rendering (e.g., Skia in Blink/WebKit).

Advantages of an Integrated System

• Efficiency: CSS handling is integrated with HTML parsing and rendering, reducing overhead.
• Dynamic Updates: The tight coupling allows immediate style updates in response to JavaScript changes or user interactions.
• Cross-Compatibility: A unified engine ensures consistent rendering across CSS, HTML, and JavaScript.

Conclusion

The browser engine (e.g., Blink, Gecko) includes a CSS subsystem rather than relying on a separate engine. This integration ensures smooth coordination between styling, layout, and rendering.