What is the main difference between Selenium 1 and Selenium 2?

Selenium is a suite of software widely used in the field of automation and testing, it has been a key player in the field of automation for a long time, it helped the testers and developers to interact and manipulate web applications seamlessly. However, the world of automation saw a significant change with the introduction of the Selenium version 2, which brought a plethora of improvements and changes into the field of Automation. This article will delve into the realm of Automation and discuss the difference between Selenium version 1 and Selenium version 2, highlighting their differences, advantages, and implications. Whether the user is an experienced Selenium user in the field of Automation testing for a long time or a complete amateur who is curious or entering the realm of automation, having knowledge about the difference between the two versions is always a plus point.

What are the different versions of Selenium?

There are currently 4 versions of Selenium available in the market –

• Selenium RC
• Selenium WebDriver
• Selenium 3
• Selenium 4 (Released this year)

Difference between Selenium 1 and Selenium 2:

The main difference between Selenium 1 and Selenium 2 lies in their internal architecture. In case of Selenium 1, which is also known as the Selenium Remote Control, required a Selenium Server and injected JavaScript functions to automate browsers, which sometimes lead into performance and stability issues. Also, it only supported a handful number of browsers and its versions.

On the other hand, Selenium version 2, known as Selenium WebDriver, which didn’t require JavaScript functions to injected into the browsers to automate the processes, it could directly interact with the browsers without needing a server. It also supported a plethora of renowned programming languages such as Java, C#, Python, Ruby etc. It enhanced support for various web technologies and browsers.

Selenium version 1:

Selenium Version, also known as the Selenium Remote Control, was a leading tool in the field of automation. It allowed the developers/testers to write automation scripts in various renowned programming languages, making it the perfect choice for the field of Automation. Selenium version 1 was operated as a proxy server, whose main work was to intercept and translate commands from the testing scripts to the web browser. This feature eased the process of interacting with the Web Elements and Verifying the Web Page Functionality.

Architecture:

• Test Script- This was the place where the test logic is being stored, this test scripts were written in various programming languages supported by Selenium RC.
• Client Libraries- Test scripts interacted with the libraries which acted like a bridge between the test script and the selenium server.
• Selenium Server- Selenium Server acted as a intermediary between the test scripts and the web browsers. It accepts the test scripts, interpret them and then inject them into the browser using JavaScript.
• JavaScript Interpreter- Selenium RC required each browser to have a JavaScript interpreter. Selenium Server injects JavaScript functions into the browsers and browsers then executes those functions which is used to automate some processes.
• Browser- The main part of the architecture in which the test scripts were executed, and web applications were tested.

The below is the architectural diagram of Selenium RC, it consists of numbers which tells about the workflow.

Features of Selenium RC:

• Cross Browser Compatibility- Selenium RC supported testing of web applications in various web browsers like Chrome, Safari, Internet Explorer, Opera, Firefox etc.
• Multiple Language Support- Selenium RC provided client libraries or language bindings for programming languages like C#, Java, PHP etc. Testers could write test scripts in language of their choice.
• Test Script Flexibility- Testers could customize the test scripts according to their needs and add complex features to test in the browser.
• HTML Test Reports- Selenium RC generated HTML based test reports that provided detailed information about the test execution and error messages. These reports were proven to be very useful for the testers.
• Flexibility of Ajax Testing- Selenium RC could handle Ajax requests (Asynchronous JavaScript and XML).

Limitations of Selenium Version 1:

Due to various limitations and complexities of Selenium Version 1, the Selenium version 2 was developed and released. Some of its limitations are given below –

• Complex Installation and Configuration- Installation and Setting up process of Selenium version 1 i.e. Selenium RC was complex, as it involved tweaking the browser’s configuration, drivers’ configuration and the Selenium Server. This complexity in installation and configuration made is hard for beginners to understand or use.
• Rely on JavaScript- Selenium RC relied on JavaScript Injection the most while interacting with web elements, this had various limitations due to dynamic nature of some web elements, JavaScript injection can’t interact with dynamic and complex web elements easily, as a result it sometimes resulted in Synchronization Errors.
• Slower Execution- Selenium Remote Control (version 1) had slower execution speed as compared to the Selenium WebDriver (version 2), as it used a JavaScript-based automation engine, which was inefficient as compared to the native automation support by the WebDriver.
• Browser Support- Selenium RC required Selenium RC Server to be running for each browser, which was inefficient as compared to the WebDriver’s approach of using Native Browser Drivers.

Selenium Version 2:

Selenium version 2, also known as the Selenium WebDriver was a huge advancement forward in the world of Web Automation. It addressed most of the limitations available in the Selenium Version 1, its predecessor, making it the most preferred application for the Automation and Testing purpose. The Web Driver provided a more intuitive and user-friendly API. It can directly interact with the browser, without the need of JavaScript injection, which was one of the major limitations in case of Selenium RC. This direct interaction with the web browser increased the execution speed, making it more efficient for test and automation purpose as compared to it’s previous version. WebDriver also supports a wide range of browsers, supports cross-domain testing, offered the support of native drivers for various browsers etc which were not available in the Selenium RC due to many restrictions. The abolition of these limitations, integrated with a more comprehensive community, robust documentation, and easier setup, has cemented Selenium WebDriver’s reputation as the industry standard for web automation, surpassing Selenium RC in nearly every aspect.

Architecture of Selenium WebDriver

• Test Script – This is the test script written by the developer using their preferred programming language.
• WebDriver API – This is an Application Programming Interface which allows the test scripts to interact with the web browser and automate some tasks such as opening and closing browsers, navigating to URLs etc.
• JSON Wire Protocol – WebDriver communicates with the Browser using this JSON Wire Protocol, this protocol sends HTTPS requests to WebDriver server, which takes care of the automation process in the browser.
• Browser Drivers – There are some specific drivers for specific browsers available which is responsible for interpreting the WebDriver commands and translate them into actions which will be performed by the browser,
• Operating System – Selenium WebDriver supports multiple Operating Systems like Windows, MAC and Linux. It is a cross platform automation testing application.

Features of Selenium WebDriver:

• Cross Browser Testing – Selenium WebDriver works on multiple renewed browsers like Google Chrome, Microsoft Edge, Firefox etc which lets the developer test their application in multiple types of browsers to check if that is working perfectly in all of them or showing any kind of error.
• Supports Multiple Programming Languages – Selenium WebDriver supports multiple programming languages like Java, C#, Python, Ruby, Scala etc, so that the developers can use their favourite language to write test scripts.
• Advanced Interactions – Selenium WebDriver supports complex and advanced interactions with the web elements, such as mouse-hover, drag and drop, handling keyboard events etc.
• Parallel Test Execution – WebDriver supports parallel test execution which reduces time and increases the efficiency of tests.
• Direct Communication with Browser – In case of Selenium RC, there was a need of Selenium Server to communicate with the Web Browser. But Selenium WebDriver could directly interact and communicate with browsers using the browser’s native drivers.
• Support for Headless Browsers – WebDriver provide support for headless browsers like Google Chrome Headless and Fire-Fox Headless, which allows faster test execution without a visible browser window.
• Continuous Integration Compatibility – Due to its improved performance WebDriver seamlessly works with CI/CD pipelines, allowing automated testing as part of SDLC.

Limitations of Selenium WebDriver:

• Limited Support for Desktop Application – Selenium WebDriver was designed to automate and test web applications primarily, it has limited capability and support for Desktop Applications.
• No built-in report generation – Selenium WebDriver doesn’t support built-in report generation, some other third-party application or frameworks are needed to generate the report of the test.
• Steep Learning Curve – Using Selenium WebDriver requires technical expertise, so those who are new to the field of automation might find it complex understanding.
• Browser Compatibility – Although WebDriver supports most of the renowned browsers, but sometimes update of those browsers can break the code which was running fine in the last version. Then that code and the Selenium driver should be updated which would be compatible with the browser version.
• No Built-in Image Testing – WebDriver doesn’t support built-in Image based testing, verification of Visual Elements requires external libraries and frameworks.
• Limited Mobile Support – Selenium WebDriver was primarily built to test Web Applications, although it has a software called Appium for mobile testing, it is not good as those who are primarily built for mobile testing.

Comparison of Selenium 1 and Selenium 2:

Topic	Selenium RC	Selenium WebDriver
Automation Methodology	It relies on the JavaScript Injection and function to interact with Web Elements and for automation process.	It can directly interact with the web elements using native methods.
Interaction with Browser	It uses JavaScript to interact with the Browsers which sometimes cause synchronization error.	It communicates with the browser directly.
Cross Domain Testing	It can’t do cross domain testing due to various browser restrictions and security policies.	It can handle and perform Cross Domain Testing seamlessly.
Simplicity of API	It has a complex and less user-friendly API.	It offers a simple and more user-friendly API which makes the test scripts more readable and maintainable.
Browser Support	Selenium RC struggles to work with most of the newer versions of the browsers.	It supports all the latest versions of the web browsers.
Elimination of Selenium Core	It relied upon Selenium Core which is a JavaScript based Automation Engine.	Selenium Core dependency was removed from the Selenium WebDriver.
Language Support	It supported a very few numbers of programming languages.	It supports a plethora of programming languages and supports most of the renowned programming languages.

Conclusion:

In the conclusion, the transition from the Selenium RC to the Selenium WebDriver represents a giant leap into the world of automation and testing. Selenium RC started the revolution in the field of Automation and Testing, and Selenium WebDriver made it easier for the people to understand for everyone whether they are new to the field of automation or experienced automation engineer or tester.

The key difference between the Selenium RC and Selenium WebDriver is the underlying architecture of them, while the traditional Selenium RC used a intermediary server to communicate with the Browser, Selenium WebDriver eliminates the need of any intermediary browser to communicate with the server, it can directly communicate with Browser. This change in architecture has enchanced speed and performance immensly.

Selenium WebDriver’s user-friendly interface makes it suitable for anyone, whether they are professional or beginner in the field of automation. Its compatibility with multiple programming renowned languages such as Python, Java, C#, Ruby etc., simpler setup, and neat syntax allow developers to write test scripts that are easier to maintain and extend. It also provides enhanced support for handling complex web elements and dynamic content, reducing the likelihood of flaky tests.