Selenium is a web automation testing tool and you can simply say selenium automates browsers. Selenium is a set of different components and software tools ( IDE, RC / WebDriver , Grid) with different approach for automating the test cases across many platforms. The official website for selenium is - http://seleniumhq.org.
Selenium was first invented in 2004 by Thougtworks and with the open source community of developers.
You can be able to test any web developments and web applications. For example, simple websites to large web portals and e-commerce websites. You can use selenium automation testing mainly for Functional testing, Re testing, Regression Testing, Cross browser functional tests etc. You can able to test all the web elements (Forms, Text boxes, Check boxes, Radio buttons, Submit buttons, Text presence and verifications, Web elements functioanlites, Certificate errors, Pop ups , Alerts, Validations, etc) on a web page.
Selenium is an open source and free to use. It supports automation testing in multiple operating systems with multiple browsers with multiple languages. You can automate the test cases with cross browsers in parallel.
It is not suitable to test windows based desktop applications & windows based software development. You need to check and update about versions and compatibilites between selenium components to Browsers. ( For example, if you are using Selenium RC 1.0, then you can able to run and test only with old versions Firefox 3.6 to 4 etc only, if you want to test with latest firefox 18, then you need to migrate to WebDriver)
It is an easy interface where you can record and play the scripts ( Test cases).
It is a part of Selenium tools.
It is a plug in for firefox browser.
It will record user actions automatically and creates script when you click on record.
You can be able to convert the recorded script into your choosen programming language.
It is a tool for building the test scripts(Test cases).
It was developed with Java script libraries and extensions.
You can create quick bug reproduction scripts.
It is best suitable for just recording and playing the scripts
You can be able to run and test with only Firefox browser, it does not support any other browsers. You need to be a java script expert to create your own commands to execute any specific requirements. The result may not accurate in some cases.
For example if you want to get the text of all hyper links and calculate the total number of hyper links on a web page like amazon, ebay websites by using IDE, it is very difficult to do that. By using RC / WebDriver, if you write and execute a small programming code for 3 to 4 lines, it will bring you the result in few seconds.
Selenium IDE - You need a firefox browser.Selenium RC / WebDriver -
You need an editor to write the programming code like java , c# etc.
You should know at least one programming language - Java , C#, PHP , Python, Perl, Ruby.
For Java - I am using Eclipse IDE as java editor.
For C# - I am using Visual Studio as C# editor..
You need to download and cofigure the selenium client drivers from selenium websites.
You need to add fire bug and fire path extensions to the firefox browser to find the x-path of the HTML elements.
Selenium RC / WebDriver is not an interface like Selenium IDE. Selenium RC / WebDriver is an API to create robust, browser-based regression automation.
RC is known as remote control and you can call it as version 1.x ( 1.0, 1.1 etc ). You can call WebDriver as version 2.x (2.0 , 2.1 etc). With WebDrvier, you have support for Java , C#, PHP , Python, Perl, Ruby programming languages with allmost latest browsers.
You can distribute and run multiple tests at the same time on different machines with different browsers with different operating systems in parallel.What is the difference between QTP and Selenium?
Developed by Mercury, after taken over by HP
It is expensive and need to pay for license
Works on windows OS Platform only
Tests desktop and web applications
Supports only VB script for programming
Has got an object repository concept
Recording the script is reliable
Core engine is VB Script
Works with IE and some old versions of firefox
Developed by Thoghtworks
It is open source and free to use
Works on all major OS platforms like windows, unix, solaris , mac etc
Tests only web applications
WD Supports C#, Java , PHP , Perl , Ruby , Python etc
Here you can implment OOPs concept
Recording the script in Selenium IDE some times not reliable.
IDE Core engine is Java Script libraries
Works allmost all the latest browsers which are available in the market