Writing a browser involves the integration of several key modules that work together to provide the ability to browse the web.

The following are the main modules in the browser:

1. user interface (UI): -provides an interface for users to interact with the browser, including address bar, forward / back buttons, bookmarks, history, etc.
2. Network engine: -responsible for communicating with the network, including sending and receiving HTTP requests, processing SSL/TLS connections, and parsing URL.
3. rendering engine (Renderer): -responsible for parsing and rendering web content, including HTML, CSS and JavaScript. This module usually uses its own JavaScript engine, such as WebKit's JavaScriptCore or Blink's V8.
4. JavaScript engine: -executes the JavaScript code in the web page. This engine needs to execute JavaScript code efficiently and safely while providing good performance.
5. Storage: -manage the local data storage of web pages, including Cookie, local storage, IndexedDB, etc.
6. Security: -responsible for handling security-related functions, such as SSL/TLS connection, homology policy, content security policy, etc.
7. plug-in system: -support browser extensions and plug-ins that allow users to add new features or modify existing ones.
8. data processing: -processing and parsing web page data, such as XML, JSON, etc.
9. Multimedia processing: -handle multimedia content in web pages, such as audio, video and pictures.
10. performance Monitoring: -Monitoring and reporting the performance of web pages, including page loading time, JavaScript execution time, etc.
11. Resource Management: -manage web resources, such as pictures, CSS files, JavaScript files, etc.
12. Cache: -caching web pages and resources to improve loading speed and performance. These modules need to work together to ensure that browsers can display web content efficiently and safely. Writing a browser requires an in-depth understanding of the functions of these modules and the interaction between them.