When you type a URL (Uniform Resource Locator) into your web browser's address bar and press Enter, several steps are involved in retrieving and displaying the requested web page.
Here's an overview of what happens:
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| what happens when you type url in browser |
1. URL Parsing:
The browser parses the URL to extract the protocol (e.g., "http://" or "https://"), domain name (e.g., "www.example.com"), and optional path or query parameters.
2. DNS Resolution:
The browser checks its cache to see if it already knows the IP address associated with the domain name. If not, it sends a DNS (Domain Name System) query to a DNS server to resolve the domain name into an IP address.
3. TCP Connection:
The browser establishes a TCP (Transmission Control Protocol) connection with the web server at the resolved IP address. This connection is established on port 80 for HTTP or port 443 for HTTPS.
4. HTTP Request:
The browser sends an HTTP request to the web server. This request includes the method (e.g., GET), the path, headers, and other information. If the URL uses HTTPS, the communication is encrypted using TLS/SSL.
5. Server Processing:
The web server processes the request, retrieves the requested resource (such as an HTML file), and may perform additional server-side processing. This could involve interacting with databases or executing server-side scripts.
6. HTTP Response:
The web server sends back an HTTP response to the browser. This response includes a status code (indicating whether the request was successful, redirected, or encountered an error) and the requested content.
7. Rendering:
The browser receives the response and begins rendering the web page. It parses HTML, executes JavaScript, and applies CSS to display the content properly.
8. Rendering Completion:
The browser continues to load additional resources linked from the HTML (such as images, stylesheets, and scripts) to complete the rendering of the entire web page.
9. Display:
The fully rendered web page is displayed in the browser for the user to interact with.
Throughout this process, various optimizations, such as caching, may be employed to enhance the speed and efficiency of page loading. Additionally, if the URL uses HTTPS, the data exchanged between the browser and server is encrypted to ensure security and privacy.
