Selenium is one of the most popular set of tools which are used for automating cross-browser web-applications. Selenium works on common operating systems - Windows, Linux/Unix and Mac and supports all major browsers like Chrome, Firefox, Internet Explorer, Edge, Opera etc. It also supports different programming languages like C#, Java, Javascript, Python, Ruby etc. This gives you the flexibility to the write the automation script in the same language in which the application under test is developed, though this is not a requirement. You can use any language of your choice for writing automation script. Selenium Components : Selenium IDE is mainly a browser add-on/extension mainly used for recording / replaying the script. Selenium RC (Remote Control) would inject Javascript into browsers. This is now depreceated and is now replaced with Selenium Web Driver. Selenium Webdriver allows you to create test scripts using the progamming language of your choice through the language bindings