Browser Engines: The Crux Of Cross Browser Compatibility

What Is A Browser Engine?

A browser engine can be thought of as the heart of a browser, it helps to present the content of a website after you hit the URL of the web address you wish to visit. It does so by understanding the HTML, CSS, and JavaScript written on your web page. Sounds pretty simple, isn’t it? Well, not really, because browser engines are uniquely designed for every browser. Which is why each browser engine has its own way of interpreting the web, leading to cross browser compatibility issues.

  1. JavaScript Engine

How JavaScript & Rendering Engine Came Into The Picture?

The first time the internet came into the world, very few people had access to it. The user and the developer both were very few in number and the websites that were developed were static and simple. It was not like what it is today. Nobody knew about the dynamic functionality of the website. Actually, how would have they? Javascript was not born and was not required as such at that time. The invention of the browser engines started when Netscape and Microsoft started competing with each other for the popularity of their browsers.

How Do They Differ? Rendering Engine And JavaScript Engine

Earlier everything was done by browser engines only but the modern web continues to develop at a pace where it became troublesome for the browser engine to handle it alone. As a result, it introduced 2 types of engine JavaScript Engine and Rendering Engine. Let us understand how these Engines contributes to the overall rendering experience of a browser.

1. Rendering Engine

A rendering engine is often used interchangeably with browser engines. It is responsible for the layout of your website on your audience’s screen. You are able to read this font in grey color because of the rendering engine. A rendering engine is responsible for the paint, and animations used on your website. It creates the visuals on the screen or brightens the pixels exactly how they are meant to be to give the feel of the website like how it was made to be. So when we say the page is rendered correctly on the screen, we are actually appreciating the rendering engine capabilities. Here is a list of rendering engines produced by major web browser vendors.

  1. WebKit — Used in Safari browsers.
  2. Gecko — Used in Mozilla Firefox browsers.
  3. Trident — Used in Internet Explorer browsers.
  4. EdgeHTML — Used in Edge browsers.
  5. Presto — Legacy rendering engine for Opera.

2. JavaScript Engine

JavaScript engine as the name suggests helps to interpret JavaScript code of your website before rendering it in front of your audience. JavaScript Engines were introduced with the purpose of serving themselves as an interpreter.However, every modern browser engine uses them as a compiler to drive faster results with improved performance. Here is a list of JavaScript engines produced by major web browser vendors.

  1. Nitro — Used with Webkit
  2. SpiderMonkey — Used with Gecko
  3. Chakra — Used with Trident & EdgeHTML

Why Should You Care About Browser Engines?

A browser engine is much more than just translating the text and running it on the display with the help of rendering section. Let’s see the features of browser engine:

How Do Browser Rendering Engines Work?

The primary function of a browser rendering engine is to visualize the content requested by users in an interactive view. For instance, if a user requests an HTML script content, the rendering engine’s job is to parse the CSS and HTML. Henceforth, the content is displayed after being parsed through a rendering engine. The scalable dimension-based format ensures a rendered display significantly restoring an original page layout interpreted from its original form, while indulging scaling and panning features of the web content in real-time environment. The interaction between the end-user through an interface & the rendering engine is facilitated by the browser engines. It facilitates with a high-level interface between the User Interface and Rendering engine.

  • Rectangles arranged with specific colours are manageably sorted inside the rendered tree.
  • After the creation of a rendered tree, a layout process is followed where nodes are defined by a precise set of coordinates, which leads them to be visualized on the user-screen.
  • Considering ‘painting’ the final stage in the process, each node of the render tree is defined as per the code written in the backend layer of the user interface.
  • Browser engine is responsible to start loading of a URL and considering care of processes of reloading, backing and forward browsing actions.
  • When a user is supposed to insert a URL in the address space, UI takes the address to the browser engine where it search the domain name out of the URL and confirms its existence in browser and OS caches. If the domain name is not found in both browser and OS caches, then it requests to the Internet Service Provider (ISP) to extract the IP address from Domain Name System (DNS). Hereby, the website receives a request from the browser to retrieve its content.

Top Browser Rendering Engines Available In The Market

The knowledge of a concept or software is half complete till you do not get to know about the examples or products that have been developed with the same technology. In this section, we will look at the list of top browser engines available in the market and the browsers that have been developed using those browser engines.

Webkit Browser Rendering Engine(Safari)

Webkit browser engine is used in the development of the browser Safari that is used in the Apple operating system and other browsers that Apple uses in its application. Webkit is an old browser engine launched in 1998 and is still one of the top browser engines in the market. Webkit is written in C++ language. In 2013, Google also announced that it will be using a component of Webkit called WebCore in its own browser engine’s future releases.

Blink Browser Rendering Engine(Google Chrome & Opera)

Blink browser engine is used in the development of Google Chrome and other google projects. The component that we mentioned in the above section in Webkit browser engine about WebCore is the same component using which Blink has been developed. Blink has been developed with a huge contribution from various giants such as Samsung, Google, Facebook, Microsoft, Adobe, etc. Blink has been used since 2013 only for chrome i.e. from version 28 onwards. Before Blink, Google was using Webkit for developing chrome. Blink has been written in C++ language.

Gecko Browser Rendering Engine(Mozilla Firefox)

Gecko browser engine is developed by the Mozilla corporation and as you can guess, it is used in the Firefox browser along with the other projects. Gecko was an ambitious project when it got started in 1997 in Netscape. The need arose from the increasing complexities of the websites and the slow engine Netscape was previously having. Gecko remains one of the top choice if you are developing an application that needs to display the web pages. Gecko was started in C++ and JavaScript. Since 2016, Rust has also been included in the programming languages used for its development.

Trident Browser Rendering Engine(Internet Explorer)

Trident was released to be used as a browser engine in Microsoft’s Internet Explorer. It was developed as an essential software component in Windows applications. Apart from the Internet Explorer, it has also been used in web browsing applications like Avant Browser, Maxathon and in application programs like AOL Instant Messenger, Google Talk, Valve Steam, Pandion and many others. Although, some of the microsoft products are no longer using Trident as their browser engine which has made Microsoft to develop a state-of-the-art replacement for this 11 years old software. There were hearsays about the replacement of Trident from Internet Explorer 7 by Tasman, but Trident still continues to remain Microsoft’s primary choice as a browser engine in Internet Explorer 8 Beta.

EdgeHTML Browser Rendering Engine(Edge)

Edge as we know, is a modern web browser brought up by Microsoft. It is only natural that it got forked from Trident which as we know by now, is the rendering engine for Internet Explorer. EdgeHTML was first introduced in 2014 for Windows 10. Now, Microsoft is working to bring a Chromium-based Edge browser. Being Chromium-based, the new Edge browser will make use of Blink engine. Does that mean we could bid farewell to EdgeHTML?

Presto Browser Rendering Engine (Opera Version 7–15)

Presto browser engine will not be heard by you if you have just started to understand browser engines. Presto has become the part of history recently when Opera browser started using Blink browser engine and stopped working in Presto for its development. It must be clear by now that Presto was owned by Opera and used for Opera web browser and other applications of Opera. Since it was privately designed exclusively for Opera applications only, Unlike Blink, Presto was not open source and was internal to the organisation. Presto was observed in Opera browser version 7 till 15. Since 2013, after the birth of Blink, development using Presto has been stopped.

Future of Browser Engines

Browser engines have come a long way and to be honest, not all of them could survive this war. Many have died and many are wounded. The browser engine that started this war namely Trident, is deprecated today but the other one Gecko is still in it.

Why Cross Browser Testing Is Pivotal For Different Browser Engines?

By far we are sure of two things. One, every browser has a unique way of rendering a website. And two, not all your website visitors are using the same browser. Where does that bring us?

The list is actually very extensive and you can find it from the original source.

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