This document discusses continuous integration testing using Yahoo! User Interface Library (YUI) Test, Selenium, and Hudson. It begins with an introduction to continuous integration and how YUI Test allows for unit testing JavaScript code. It then covers how Selenium allows for browser-based testing and can be used with YUI Test. The document demonstrates how Hudson can be used as a continuous integration server to run tests automatically on code commits. It provides live demos of using YUI Test and Selenium together, and integrating them with Hudson for continuous testing.