The Internet And The World Wide Web (Copy)
IGCSE / O Level Computer Science Cheat Sheet
Topic: 5.1 The Internet and the World Wide Web
🌐 Internet vs World Wide Web
| Term | Description |
|---|---|
| Internet | Physical infrastructure: cables, routers, servers, etc. |
| World Wide Web | Collection of websites and web pages accessed via the internet |
🔗 URL (Uniform Resource Locator)
- Text-based address used to locate a resource on the web
- Example:
https://www.example.com/index.html
Parts of a URL:
| Part | Example | Meaning |
|---|---|---|
| Protocol | https:// |
Communication method |
| Domain name | www.example.com |
Web server address |
| File path | /index.html |
Specific resource or page |
📡 HTTP vs HTTPS
| Protocol | Stands For | Description |
|---|---|---|
| HTTP | Hypertext Transfer Protocol | Used to transfer web pages |
| HTTPS | HTTP Secure | HTTP + encryption (SSL/TLS) for security |
🌍 Web Browser
Used to access and display web content
Key Features:
- Renders HTML pages
- Stores bookmarks, cookies, and history
- Supports multiple tabs
- Provides address bar and navigation tools
📥 How Web Pages are Retrieved
- User enters URL in browser
- Browser sends request to DNS to resolve domain name to IP
- Request is sent to the web server
- Web server sends back HTML data
- Browser renders the content
🍪 Cookies
- Small data files stored on the user’s device by websites
| Type | Purpose |
|---|---|
| Session cookies | Temporary; deleted when browser closes |
| Persistent cookies | Remain after browser closes; used for login, prefs |
Uses:
- Store login info
- Save cart items
- Track user preferences
- Personalize experience
🔁 Related Components
| Component | Role |
|---|---|
| Web Server | Hosts website content |
| Browser | Displays HTML and web content |
| DNS | Translates domain name to IP address |
| IP Address | Identifies devices on a network |
| HTML | Language used to write web pages |