This document discusses browser architecture and cross-browser testing. It begins with an introduction from Sang Bui and information about their current project testing browsers on multiple platforms. It then provides details on browser architecture including the user interface, browser engine, rendering engine, and other components. The document discusses differences between Firefox, Chrome, and IE architectures. It also covers cross-browser testing and how to set up environments to test across browsers, as well as client-side testing and ways to bypass client-side validation.