Chapter 2: Web Development Basics
Chapter 2: Web Development Basics
2.1 How the Web Works
The World Wide Web operates on a client-server model where clients (browsers) request resources from servers. Understanding this fundamental architecture is essential for web development.
HTTP Protocol: HyperText Transfer Protocol (HTTP) is the foundation of data communication on the web. When you visit a website, your browser sends an HTTP request to the server, which responds with the requested resource.
Request-Response Cycle:
- User Action: User types a URL or clicks a link
- DNS Lookup: Browser resolves domain name to IP address
- HTTP Request: Browser sends request to server
- Server Processing: Server processes request and generates response
- HTTP Response: Server sends response back to browser
- Rendering: Browser renders the HTML, CSS, and JavaScript
HTTP Methods:
- GET: Retrieve data from server (viewing pages, fetching data)
- POST: Submit data to server (form submissions, creating resources)
- PUT: Update existing resource on server
- DELETE: Remove resource from server
- PATCH: Partially update resource
// Example HTTP Request
GET /index.html HTTP/1.1
Host: www.example.com
User-Agent: Mozilla/5.0
Accept: text/html
// Example HTTP Response
HTTP/1.1 200 OK
Content-Type: text/html
Content-Length: 1234
<html>...</html>2.2 Web Technologies Overview
Modern web development involves multiple technologies working together:
Browsers: Web browsers (Chrome, Firefox, Safari, Edge) interpret HTML, CSS, and JavaScript to display web pages. Each browser has its own rendering engine and JavaScript engine.
Servers: Web servers (Apache, Nginx, Node.js) handle HTTP requests, process server-side code, and serve responses. They manage routing, authentication, and database interactions.
Databases: Store and manage application data. Relational databases (MySQL, PostgreSQL) use tables and relationships, while NoSQL databases (MongoDB) use documents or key-value pairs.
How They Interact:
- Browser requests a page from server
- Server processes request, queries database if needed
- Server generates HTML response with data
- Browser receives HTML and renders page
- Browser executes JavaScript for interactivity
- JavaScript may make additional API requests to server
2.3 URLs and Web Addresses
Uniform Resource Locators (URLs) identify resources on the web:
URL Structure:
https://www.example.com:443/path/to/page?query=value#section
Protocol: https://
Domain: www.example.com
Port: :443 (default for HTTPS)
Path: /path/to/page
Query: ?query=value
Fragment: #sectionProtocols:
- HTTP: HyperText Transfer Protocol (unencrypted)
- HTTPS: HTTP Secure (encrypted with SSL/TLS)
- FTP: File Transfer Protocol for file uploads
2.4 Web Standards and Best Practices
Following web standards ensures compatibility and accessibility:
HTML Standards: Use semantic HTML5 elements, proper document structure, and valid markup.
CSS Standards: Follow CSS best practices, use modern features, and ensure cross-browser compatibility.
JavaScript Standards: Write clean, maintainable code following ES6+ standards and best practices.
Accessibility: Ensure websites are accessible to users with disabilities using proper ARIA labels, alt text, and keyboard navigation.
Performance: Optimize page load times, minimize HTTP requests, compress assets, and use caching strategies.