# How a Browser Works: A Beginner-Friendly Guide to Browser Internals

A browser is a software application that allows you to access and view websites on the internet. When a user requests a web page from a particular website, the browser retrieves its files from a web server and then displays the page on the user's screen.

It retrieves web pages, displays text, images, and videos, and lets you interact with online content.

## **How do Browsers Work?**

* You enter a website address (URL) or click a link.
    
* The browser sends a request to the website’s server.
    
* The server responds by sending the webpage’s data (HTML, CSS, JavaScript, images, etc.).
    
* The browser processes this data and displays the webpage.
    
* You can interact with the page by clicking, scrolling, or entering information.
    

![How does a Browser Work](https://browserstack.wpenginepowered.com/wp-content/uploads/2023/06/How-does-a-Browser-Work.png align="center")

**Step 1**: The process begins with Domain Name System (DNS) resolution, where the browser translates the domain name into an IP address to locate the server where the web page is stored.

**Step 2**: The browser then sends an HTTP request to the server, specifying the path and parameters of the requested resource.

**Step 3**: Once the server receives the request, it sends an HTTP response to the browser containing the requested resource in HTML, CSS, and JavaScript code.

**Step 4**: The browser’s rendering engine interprets and renders the code to display the web page on the user’s device.

**Step 5**: The CSS stylesheets are applied to format the web page’s content, including fonts, colors, and layout.

**Step 6**: The browser may also execute JavaScript code on the web page to add interactivity and dynamic behavior.

**Step 7**: As new content is loaded or changes are made to the web page, the browser updates the display accordingly.

## Features of a Browser

Most browsers include standard features such as:

* A **home button** to return to a designated homepage
    
* An **address bar** to enter web **URLs**
    
* **Back** and **forward** buttons for page navigation
    
* A **refresh** button to reload pages
    
* **Stop** to halt page loading
    
* **Tabs** for multiple websites in one window
    
* **Bookmarks** for saving frequently visited sites
    

Many browsers support plug-ins to enhance functionality, like adding security features or new capabilities.

## Components of a Browser

Web Browsers consist of 7 different components listed below:

#### **1\. User Interface**

This component allows end-users to interact with all visual elements available on the web page. The visual elements include the **address bar, home button, next button,** and all other elements that fetch and display the web page requested by the end-user.

#### **2\. Browser Engine**

It is a core component of every web browser. The browser engine functions as an intermediary or a bridge between the user interface and the rendering engine. It queries and handles the rendering engine as per the inputs received from the user interface.

The performance and features of a browser engine can greatly impact the user experience of a web browser. A fast and efficient browser engine can help web pages load quickly and smoothly, while a slower or less capable engine may struggle to render complex pages or provide a smooth browsing experience.

#### **3\. Rendering Engine**

As the name suggests, this component is responsible for rendering a specific web page requested by the user on their screen. It interprets HTML and XML documents along with images that are styled or formatted using CSS, and a final layout is generated, which is displayed on the user interface.

**Note**: Every browser has its own unique rendering engine. Rendering engines might also differ for different browser versions. The list below mentions browser engines used by a few common browsers:

1. Google Chrome and Opera v.15+: **Blink**
    
2. Internet Explorer: **Trident**
    
3. Mozilla Firefox: **Gecko**
    
4. Chrome for iOS and Safari: **WebKit**
    

#### **4\. Networking**

This component is responsible for managing network calls using standard protocols like HTTP or FTP. It also looks after security issues associated with internet communication.

#### **5\. JavaScript Interpreter**

As the name suggests, it is responsible for parsing and executing the JavaScript code embedded in a website. Once the interpreted results are generated, they are forwarded to the rendering engine for display on the user interface.

#### **6\. UI Backend**

This component uses the user interface methods of the underlying operating system. It is mainly used for drawing basic widgets (windows and combo boxes).

#### **7\. Data Storage/Persistence**

It is a persistent layer. A web browser needs to store various types of data locally, for example, cookies. As a result, browsers must be compatible with data storage mechanisms such as WebSQL, IndexedDB, FileSystem, etc.

When users type a URL, click links, or utilize features, the front-end requests necessary resources from the back-end. The back-end processes these resources and sends the rendered content back to the front-end for display. This enables smooth navigation and interaction with online content.

Apart from these two major elements, here are the components of a browser.

![Components of a browser](https://browserstack.wpenginepowered.com/wp-content/uploads/2023/06/Components-of-a-browser.png align="center")

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1769949930462/487d76a1-dd18-4b5f-b614-6713a827bdb4.png align="center")