Selenium 3 Vs Selenium 4 - Key Differences

Selenium 3 vs Selenium 4Transitioning from Selenium 3 to Selenium 4 represents a leap forward in web automation. In this blog, you will learn the critical differences between Selenium 3 vs Selenium 4, from its advanced WebDriver to improved debugging tools. We’ll dissect the key differences between the versions, emphasising why the upgrade is not just necessary but beneficial. 

Join us as we explore the intricacies of Selenium 3 vs Selenium 4, equipping you with the knowledge to harness the full potential of these powerful automation frameworks.

Table of Contents 

1) Selenium 3: Architecture 

2) Selenium 4: Architecture 

3) What are the differences between Selenium 3 and Selenium 4 

   a) Extension of Chrome Driver 

   b) Client and Server Communication System 

   c) Starting the Hub & Node Jars 

4) Conclusion 

Selenium 3: Architecture 
 

The architecture of Selenium 3 is based on Selenium WebDriver, Selenium Grid for parallel testing, and Browser Drivers for browser communication.  It enables testers to automate Web Application Testing across different browsers and platforms.  

Selenium 3 follows a client-server architecture consisting of four major components. Let’s explore them below:

1) Selenium Client Library

2) Language Bindings

3) JSON Wire Protocol using HTTP

4) Browser Drivers

The architecture of Selenium 3 is based on the JSON Wire Protocol. JSON stands for JavaScript Object Notation. JSON Wire Protocol reduces communication complexity between Client and Server by using HTTP (Hypertext Transfer Protocol).

The JSON Wire Protocol is employed for data transmission between the client and server via HTTP Hypertext Transfer Protocol. In plain words, when a request originates from a Selenium client, it travels through HTTP and is received by the JSON Wire Protocol. The  Browser Driver guarantees the safety of this request. The next step is response generation by the server once the request is processed.  After this, the response is sent back to the client for processing.
 

Selenium 4: Architecture

Selenium 4 provides architectural changes and improvements when compared to Selenium 3. The innovative element is the incorporating  the Selenium DevTools API as the W3C standard. Due to this, the architecture is handled in a more closely integrated and thoughtful manner. In Selenium 4, the Selenium WebDriver architecture consists of the following four major components

1) Selenium Client Libraries

2) Binding Languages

3) WebDriver W3C Protocol

4) Browser Drivers

All the elements in Selenium WebDriver 4 are comparable with those in Selenium 3 except the JSON Wire Protocol, which is replaced by the new W3C WebDriver protocol. Now, let’s understand this in detail.

In Selenium 4, communication between the client and server is facilitated through the W3C WebDriver protocol. This protocol is adhered to by the latest versions of major browsers, such as Internet Explorer, Firefox, and Chrome, ensuring they are W3C-compliant. 

The client-side comprises two principal components: the Selenium Client and the WebDriver Language Bindings. On the server side, the Browser Drivers represent the server’s functionality, interpreting the Selenium commands into actions within the browser.

The Selenium Client makes a request to run a command. WebDriver Language Bindings are mainly used for operations. After running an automated test script on the web browser, a Browser Driver will receive and respond to the command from the client.

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What is the differences between Selenium 3 and Selenium 4 

Although Selenium 4 is the successor of Selenium 3, there are a few differences between them, that should be noted. If you have a grasp on the architectures of both, then the differences will be easier to understand. Here are the key differences between Selenium 3 and Selenium 4: 

Extension of Chrome Driver 

The first major difference between Selenium 3 and Selenium 4 is regarding the extension of Chrome Driver. In Selenium 3, the Chrome Driver is extended to the Remote WebDriver. But in Selenium 4, the Chrome Driver itself is extended.

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Client and Server Communication System

The second key difference  is based on the mode of communication used by both. As mentioned in the Architecture, Selenium 3  uses of the JSON Wire Protocol for information transfer between client and server. However, Selenium 4 does not depend on the JSON Wire Protocol. It uses the W3C consortium to facilitate communication between the client and server. 

Starting the Hub & Node Jars 

The start of the Hub and Node Jars is the third major difference between Selenium 3 and Selenium 4. In Selenium 3, the Hub and Node Jars must be started in order to perform automation. In Selenium 4, the Hub and Jar nodes do not need to be started for the automation testing process.   

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Conclusion 

Both Selenium 3 and Selenium 4 are beneficial additions to the quality testing processes of web applications. By understanding the Selenium prerequisites, you can ensure you are optimally utilising Selenium for Web Application Testing. We hope the contents of this blog have helped you understand the key points and differences in the Selenium 3 vs Selenium 4 debate. 

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