Web Engineering - BSCS Notes

Web Engineering — Complete BSCS Notes

World Wide Web Architecture

Definition: WWW is a system of interlinked documents accessed via internet.
Architecture:
Client (Browser) → Server → Database
Example: User opens Google → request sent to server → response returned

Protocols & Standards

HTTP: Communication protocol between client & server
HTML Example: <html> <body> <h1>Hello World</h1> </body> </html>
XML Example: <user> <name>Ali</name> </user>

Web Technologies & Tools

Scripting: JavaScript, PHP
JavaScript Example: function show(){ alert("Hello User"); }
PHP Example: <?php echo "Hello World"; ?>
Servers: Web server (Apache), App server

Web-Based Applications

Definition: Applications accessed via browser
Examples: Search engines, CMS (WordPress)
Example Flow:
User → Search → Server → Results

Web Services

Definition: APIs that allow communication between apps
Example (JS Fetch): fetch("https://api.example.com") .then(res => res.json()) .then(data => console.log(data));

Web2, Semantic Web & Web3

Web2: Interactive web (social media)
Semantic Web: Meaningful data (AI-based)
Web3: Blockchain-based decentralized web

Website Design Principles

Concepts:
Usability, Navigation, Responsiveness
Example CSS: body{ background:#eee; }

Practical Website Development

Steps:
1. Design UI
2. Write HTML/CSS
3. Add JS
4. Connect backend
Mini Example: <button onclick="alert('Hello')">Click</button>