This document provides an overview of Selenium, an open source web application testing framework. It can run tests across different browsers and platforms. Selenium allows simulating user interactions like navigating web pages and making assertions to validate pages. Tests can be recorded using the Selenium IDE Firefox plugin and played back with assertions. A test suite is a HTML file containing links to individual test case files. The Selenium IDE test runner allows executing the test suite and controlling the test execution speed and log output.