Used for questions about using Selenium WebDriver, a browser automation framework frequently used to automate testing in a browser.
Selenium WebDriver is the successor to Selenium RC. Selenium WebDriver accepts commands (sent in Selenese, or via a Client API) and sends them to a browser. This is implemented through a browser-specific browser driver, which sends commands to a browser, and retrieves results. Most browser drivers actually launch and access a browser application (such as Firefox or Internet Explorer); there is also an HtmlUnit browser driver, which simulates a browser using HtmlUnit.
Unlike in Selenium 1, where the Selenium server was necessary to run tests, Selenium WebDriver does not need a special server to execute tests. Instead, the WebDriver directly starts a browser instance and controls it. However, Selenium Grid can be used with WebDriver to execute tests on remote systems (see below). Where possible, WebDriver uses native operating system level functionality rather than browser-based JavaScript commands to drive the browser. This bypasses problems with subtle differences between native and JavaScript commands, including security restrictions.
In practice, this means that the Selenium 2.0 API has significantly fewer calls than does the Selenium 1.0 API. Where Selenium 1.0 attempted to provide a rich interface for many different browser operations, Selenium 2.0 aims to provide a basic set of building blocks from which developers can create their own Domain Specific Language. One such DSL already exists: the Watir project in the Ruby language has a rich history of good design. Watir-webdriver implements the Watir API as a wrapper for Selenium-Webdriver in Ruby. Watir-webdriver is created entirely automatically, based on the WebDriver specification and the HTML specification.
As of early 2012, Simon Stewart (inventor of WebDriver), who was then with Google and now with Facebook, and David Burns of Mozilla were negotiating with the W3C to make WebDriver an internet standard. In July 2012, the working draft was released. Selenium-Webdriver (Selenium 2.0) is fully implemented and supported in Python, Ruby, Java, and C#.
