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The Architecture of the World Wide Web
The World Wide Web (WWW) is an information space where documents and web resources are identified by Uniform Resource Locators (URLs), interlinked by hypertext links, and accessible via the internet. In A/L ICT Unit 10, students study the technologies that power modern websites.
1. The Client-Server Model
Web communication operates on a request-response protocol:
- Client (Browser): Sends an HTTP/HTTPS request to a web server requesting a webpage, image, or resource.
- Web Server: Processes the request, fetches data from databases if needed, and returns the appropriate HTTP status code (e.g., 200 OK, 404 Not Found) alongside the requested content.
- Stateless Nature of HTTP: HTTP is stateless, meaning each request is treated independently without knowledge of previous requests. Technologies like cookies and session tokens maintain user state across requests.
2. Semantic HTML5 Markup
Semantic HTML introduces tags that describe their meaning to both the browser and search engines, rather than purely presenting content:
<header> <h1>ICT Foundation Learning Portal</h1> <nav> <ul> <li><a href="/courses">Courses</a></li> <li><a href="/blog">Blog</a></li> </ul> </nav> </header> <main> <article> <h2>Understanding Web Standards</h2> <p>Web standards ensure consistency across all browsers.</p> </article> </main> <footer> <p>© 2026 ICTF. All rights reserved.</p> </footer>3. CSS3: Cascading Style Sheets
CSS separates visual presentation from structural HTML content. Essential styling concepts include:
- The Box Model: Every HTML element is modeled as a box consisting of Content, Padding, Border, and Margin.
- Selectors: Element selectors (p), Class selectors (.highlight), ID selectors (#header), and Pseudo-classes (:hover).
- Responsive Design: Using CSS Media Queries (@media (max-width: 768px)) to adapt layouts for mobile devices and desktop monitors.
