Selenium is an open source automation testing tool for web based applications. It’s easy to use and very flexible. Works on multiple browsers and multiple operating systems as compared to other tools in market. It support Android and Iphone Testing. You can use open source frameworks such as Junit, TestNG etc. and can write selenium test cases.
Languages supported by Selenium: Java, C#, Ruby, Pyton, PHP Pearl
Browsers supported by Selenium: FireFox, IE 6, 7, 8, Google chrome, Opera 8,9,10
Operating systems Supported by Selenium include: Windows, Mac, Linux, Unix
Components of Selenium: Selenium IDE, Selenium RC, WebDriver , Grid