Getting started with Selenium Webdriver:

In this post we will learn,

1. What is Selenium?
2. What is Selenium WebDriver?
3. Why/Where to use Webdriver?
4. Difference between Selenium IDE, RC and Webdriver?
5. Flexibility and Extensible of Webdriver?

What is Selenium?

Selenium is a browser based open source test automation tool which automates the user interactions with the browser. It is a suite of various tools. Selenium's tool suite includes,

• Selenium IDE:  Selenium IDE (Integrated Development Environment) is a prototyping tool for building test scripts. It is a Firefox plugin and provides an easy-to-use interface for developing automated tests. Selenium IDE has a recording feature, which records user actions as they are performed and then exports them as a reusable script in one of many programming languages that can be later executed. The IDE looks like this, 
  
                             
• Selenium RC: Selenium RC was the main Selenium project for a long time. Selenium works using javascript injection. If you have worked with selenium for sometime, then you must be aware of the same origin policy issues and limitations of javascript injection. Webdriver overcomes this by using a driver for each browser. For firefox this means, webdriver attaches itself to browser as an addon, for IE it uses automation atoms and for chrome and opera it uses the chrome driver. It ‘injects’ javascript functions into the browser when the browser was loaded and then used its javascript to drive the AUT within the browser.
• Selenium Webdriver:  WebDriver is designed to provide a simpler, more concise programming interface in addition to addressing some limitations in the Selenium-RC API. Selenium-WebDriver was developed to better support dynamic web pages where elements of a page may change without the page itself being reloaded. WebDriver’s goal is to supply a well-designed object-oriented API that provides improved support for modern advanced web-app testing problems.

What is Selenium WebDriver?

WebDriver is designed to provide a simpler, more concise programming interface in addition to addressing some limitations in the Selenium-RC API. Selenium-WebDriver was developed to better support dynamic web pages where elements of a page may change without the page itself being reloaded. WebDriver’s goal is to supply a well-designed object-oriented API that provides improved support for modern advanced web-app testing problems.

Selenium-WebDriver makes direct calls to the browser using each browser’s native support for automation. How these direct calls are made, and the features they support depends on the browser you are using, i.e,

• Firefox:  Webdriver controls the Firefox browser using a Firefox plugin. The Firefox Profile that is used is stripped down from what is installed on the machine to only include the Selenium WebDriver.xpi (plugin).
• IE: This browser is controlled by a .dll and is thus only available on Windows OS. 
• Chrome:  This is maintained / supported by the Chromium project iteslf. WebDriver works with Chrome through the chromedriver binary (found on the chromium project’s download page). You need to have both chromedriver and a version of chrome browser installed. chromedriver needs to be placed somewhere on your system’s path in order for WebDriver to automatically discover it. The Chrome browser itself is discovered by chromedriver in the default installation path. These both can be overridden by environment variables. Please refer to the wiki for more information.

Why/Where to use Webdriver?

Why:

• Webdriver is a open-source tool.
• Provides various language APIs(i.e, Java, C#, Ruby..etc)
• Supports all major browsers( i.e, Firefox, Chrome, Internet Explorer and Opera and so on).
• Supports all major platforms( i.e, Windows, Linux, Mac and so on..)
• Can add user extensions.

Where:

Selenium Webdriver can be used to automate only web based applications but not desktop applications

Difference between Selenium IDE, RC and Webdriver?

Flexibility and Extensible of Webdriver?

Flexibility:
Selenium is highly flexible,

• There are many ways you can add functionality to both selenium test scripts and Selenium's framework to customize your test automation using own client libraries.
• In addition, since Selenium is open-source, the source code can be always downloaded and modified.
• Selenium supports for multiple programming and scripting languages allows the test automation engineer to build any logic they need in to their automated testing