Why We Use Selenium Components

What is Selenium:

1. Selenium is an automation tool for web application uses to perform Functional testing
2. Developed in 2004 by Jason Huggins as a JavaScript library which is used to automate manual testing routines
3. An open source  tool which means it involves no cost
4. Supports many languages like Java, Ruby, Python, C#, Perl, HTML
5. Supports multiple browsers like Chrome, Firefox, Safari, IE
6. Designed in such a manner so that test writing becomes quite easy
7. Selenium is not just a single tool or a utility, rather a package of several testing tools and for the same reason it is referred to as a 
      Suite

Components of selenium

Selenium is made up of 4 Components

-- Selenium IDE
-- Selenium RC
-- Selenium WebDriver
-- Selenium Grid

Selenium IDE

1. IDE - Integrated Development Environment
2. The simplest tool in the selenium suite
3. A Firefox add-on that creates test very quickly through its record and playback functionality
4. Used as a prototyping tool, not an overall solution for developing and maintaining complex test suites.
5. Add the IDE plugin on Firefox for installation.
6. IDE will help with record and playback functionality of scripts. 
7. Validation and assertions can be added on the recorded scripts to check the validations and the breakpoints

Selenium RC

1. RC - Remote control is also known as Selenium 1
2. When IDE failed, Selenium RC came into existence. 
3.RC Works as a server  between the user created code in JAVA Script language and the browser
4. This is the limitation of RC which needs to overcome because through RC the scripts execution time of the automation becomes quite large
5. To overcome the limitation of RC Webdriver came into existence
6. However, RC is hardly used

Selenium WebDriver

1. In today’s time, Automation testing is becoming very popular using Selenium WebDriver
2. Selenium WebDriver is an Interface and it directly interacts with the browser. It does not require any server  for interaction
3. It is a web automation framework that allows you to execute your tests against different browsers, not just Firefox (unlike Selenium IDE)
4.WebDriver also enables you to use any supporting  programming language in creating your test scripts
5. In this, you can also use looping and conditional statements in your test scripts
6. Selenium RC and WebDriver were merged to form Selenium 2.

Selenium Grid

1. Selenium Grid is used for launching the multiple browsers with a supported operating system in parallel
2. With the use of Selenium Grid, we can run the scripts on different browser in parallel
3. It allows you to run multiple tests in parallel, on multiple machines, in a heterogeneous  environment