What is selenium IDE: Selenium-IDE (Integrated Development Environment) is a tool that you use to develop your Selenium test cases. It’s a Firefox plug-in. The 'record' button in selenium IDE enables user to record his actions and is a real time saver. Although, many-a-times, due to the external plugins used in our app, we need to manually write scripts or atleast modify the recorded scripts. Why should developers know about selenium IDE? In many of our applications, we have multiple forms and features that require testing/checking whenever we make slightest of change in our code. Selenium IDE provides