drewdaemon/browser

A toy web browser written in Python. Following the textbook at http://browser.engineering/

Browser

This is a toy browser I'm building to learn more about the workings of the web platform. I'm mostly following the excellent curriculum at https://browser.engineering.

Supported Features

Requests

• URL schemes: http:, https: (TLS), data:, file: and view-source:
• G-ZIP content encoding
• Chunked transfer encoding
• Response Caching (respects basic Cache-Control headers)

Typesetting

• Supports i, b, small, big, sup, br, p
• Supports HTML4 entities (with a few others)
• Respects soft-hyphens (­)

Window interactions

• Scroll, both with mousewheel and arrow keys
  • Prevents scrolling past end of content (harder than you might think)
• Resizing

Elements

• Parses HTML to construct DOM nodes
• Supports block and inline elements in the layout tree

Styling

• Supports tag name and descendant selectors (no classes)
• Applies inline CSS and linked stylesheets
• Respects file-order tie-breaker rule
• Robust to malformed/unsupported properties
• Supported properties
  • background-color
  • font-size (inherited, supports px and %)
  • font-style (inherited)
  • font-weight (inherited)
  • color (inherited)

Navigation

• Supports multiple tabs
• Navigation by address bar
• Back button
• Hyperlinks
• URL fragments

Misc

• Supports implicit html, head, and body tags

Screenshots

Browser in action

With layout annotations