How does browser engine work?

Browser Engine is like a translator which turns your raw code into a beautifully laid out page of text and visual graphics which you will be able to understand easily and it is the most important component of the browser. Browser engines are the main reason that a web pages look, load, work different in different browsers. We will understand the working of Browser Engine in steps so that we can easily understand it. Now, let’s look at some steps that involved in rendering the web page.

1. Whenever the user pass some URL from the User Interface the browse engine receives the URL and it sends the request to the networking component which handles the communication with the web server and retrives the HTML document and other resources like images, videos, text, stylesheets, script etc.
2. After retrieving the HTML document the browser engine passes it to the rendering engine, which parses it and constructs a tree-like data structure called Document Object Mode (DOM). The DOM simply represents the logical structures and content of the web page in a tree like structure.
3. Whenever the browser engine computed the styles, it takes the DOM and the computed style and pass it to the Layout engine that uses various algorithms to handle each element of the DOM and draw a box that holds the content and apply all the style that are instructed.
4. After the completion of layout, the engine makes a blueprint of the web page into part you usually see on the screen. This whole process is known as Painting. Every box that was defined by the layout engine get drawn of painted on the screen and user finally sees the complete web page. It also executes any scripts that are attached to the web page, which may modify the DOM or perform other actions, such as adding interactivity or animation.

All the above steps discussed do not necessarily happen in sequential or discrete it may happen that the process overlap or run in parallel it all depends on the implementation of the browser engine and the rendering engine. That’s the main reason why we see different visual representations or behaviors of same web page in different browsers.

A web browser is a software application that lets you explore the internet. It retrieves and displays web pages, images, videos, and other content from web servers. Each piece of content has a unique address called a URL (Uniform Resource Locator), which tells the browser where to find it.

While we often focus on the browser itself (Chrome, Firefox, Edge, etc.), each choice also determines the underlying browser engine and rendering engine. These core components work together to create the web experience we see. Though sometimes used interchangeably, they have distinct roles. Here, In this article, we are going to study the browser engine and how it works under the hood.