1. What a browser is
A web browser (like Chrome, Firefox, Edge, or Safari) is basically a translator between the internet and you. It takes code (HTML, CSS, JavaScript) from a web server and turns it into the websites you see and interact with.
2. Steps a browser takes when you visit a site
When you type a URL (like www.example.com) and hit enter:
Find the server
The browser uses DNS (like a phonebook) to find the IP address of the website’s server.
Request the content
The browser sends an HTTP/HTTPS request to that server asking for the web page.
Receive files back
The server responds with HTML (the structure), CSS (the styles), and JavaScript (the interactivity). Sometimes also images, videos, fonts, etc.
Render the page
The browser interprets the code and builds the page step by step:
HTML → DOM (Document Object Model): A tree structure of elements (like
,
, ).
CSS → CSSOM (CSS Object Model): The rules for how things should look.
JavaScript → JS Engine: Runs the scripts that add interactivity.
Render Tree: Combines DOM + CSSOM to know what should be painted.
Layout & Paint: Figures out sizes/positions, then draws pixels on the screen.
3. Key parts inside a browser
Networking: Handles requests to servers.
HTML parser: Reads and turns HTML into the DOM.
CSS parser: Applies styles.
JavaScript engine: Runs JS (like V8 in Chrome, SpiderMonkey in Firefox).
Renderer: Figures out how to display everything.
Compositor: Puts all the layers together and shows them on screen.
4. Why this matters for web developers
Understanding rendering helps you write efficient code (e.g., knowing how CSS and JavaScript affect performance).
Helps debug: if something isn’t showing right, you’ll know whether it’s an HTML issue, CSS styling problem, or a JavaScript script.
Helps optimize load times by reducing unnecessary files or large images.
In short:
A browser is like a chef in a restaurant. You give it a recipe (HTML, CSS, JS), it fetches ingredients (resources from the server), follows the instructions (parses code), cooks the meal (renders), and serves you the final dish (the website you see).
