Selenium components consist of Selenium IDE, Selenium RC, Selenium WebDriver, and Selenium RC.
Selenium IDE- It was basically a Firefox plugin and one of the earliest and simplest versions of Selenium. It had the record and play feature. In order to create an advanced framework, Selenium IDE has to be combined with Selenium WebDriver or RC.
Selenium IDE has some disadvantages like −
Execution time is slower.
Only supports Firefox.
No parallel execution supported.
No mobile testing supported.
Test report generation not the best.
Selenium RC does not have the record and playback option. Since it is developed on client / server architecture so to trigger the execution we need to start the server. Selenium RC provided the option of parallel and remote execution along with Selenium Grid.
Selenium Web Driver- It is a tool that overcomes the disadvantages of Selenium RC. Selenium WebDriver does not have a server and it communicates with the browser and runs it. It supports multiple platforms like Windows, Mac, and Linux and so on. Selenium WebDriver runs on various browsers like Chrome, IE, Safari and Firefox and so on. Moreover, it can be written on languages like Java, Python, C#, Ruby and so on.
Selenium Grid – It is often used for parallel execution. Selenium Grid and Selenium RC worked together to run test cases concurrently in multiple machines, browsers and platforms.
These are the main components available in Selenium Framework.