Before we dive further into Selenium 3, let's understand the differences between Selenium 2 and Selenium.

As the Selenium WebDriver has been accepted as the W3C Standard, Selenium 3 brings a number of changes to the browser implementations. All of the major browser vendors now support WebDriver specification and provide the necessary features along with the browser. For example, Microsoft came with EdgeDriver, and Apple supports the SafariDriver implementation. We will see some of these changes later in this book.

As W3C-standard WebDriver comes with a better set of APIs, which meet the expectations of most developers by being similar to the implementation of object-oriented programming.

WebDriver is being actively developed and is now supported by Browser vendors per W3C specification; you can see many advanced interactions with the web as well as mobile applications, such as File-Handling and Touch APIs.

One of the major differences introduced in Selenium 3 was the introduction of the Appium project. The mobile-testing features that were part of Selenium 2 are now moved into a separate project named Appium.

Appium is an open source mobile-automation framework for testing native, hybrid, and web mobile apps on iOS and Android platforms using the JSON-Wire protocol with Selenium WebDriver. Appium replaces the iPhoneDriver and AndroidDriver APIs in Selenium 2 that were used to test mobile web applications.

Appium enables the use and extension of the existing Selenium WebDriver framework to build mobile tests. As it uses Selenium WebDriver to drive the tests, we can use any programming language to create tests for a Selenium client library.