The Internet and The World Wide Web (Copy)

Difference between the Internet and the World Wide Web

Internet
- A global network of interconnected computers that communicate using the TCP/IP protocol suite.
- It is the infrastructure (physical + networking components) that allows computers and other devices to exchange data.
- Composed of:
  - Physical hardware (cables, satellites, routers, servers, switches).
  - Communication protocols (TCP/IP, HTTP, HTTPS, FTP, SMTP).
- Examples of services available via the internet:
  - World Wide Web (WWW)
  - Email services
  - File Transfer Protocol (FTP)
  - Streaming services (YouTube, Netflix)
  - Messaging services (WhatsApp, Messenger)
World Wide Web (WWW)
- A collection of interlinked web pages and websites accessible over the internet.
- Built using hypertext and typically written in HTML (Hypertext Markup Language).
- Accessed using a web browser such as Google Chrome, Mozilla Firefox, Microsoft Edge, Safari.
- Uses protocols such as HTTP and HTTPS to transfer and display web content.
Key Distinction:
- Internet = hardware + infrastructure.
- WWW = software layer of linked pages accessed via the internet.

A text-based address used to locate and access a resource (such as a web page) on the internet.
Components of a URL:
1. Protocol – defines the method of data transfer (e.g., http://, https://, ftp://).
2. Domain Name – the human-readable address of a website (e.g., www.example.com).
3. Path / File Name – specifies the location of a particular page or resource (e.g., /index.html).
4. Optional Parameters and Anchor Tags – used for queries and page navigation (e.g., ?id=25#section2).

Example:
https://www.educateachange.com/courses/computer-science.html

HTTP (Hypertext Transfer Protocol)
- Application-layer protocol used for transferring hypertext documents on the web.
- Defines how messages are formatted and transmitted between a client (browser) and a server.
- Does not encrypt data – more vulnerable to interception.
HTTPS (Hypertext Transfer Protocol Secure)
- Secure version of HTTP.
- Uses SSL (Secure Sockets Layer) or TLS (Transport Layer Security) for encryption.
- Encrypts data so that information such as passwords and payment details cannot be intercepted in plaintext.
- Widely used for online banking, e-commerce, and any site requiring secure data transmission.

Key Functions of HTTP/HTTPS:

Purpose: To retrieve, interpret, and render web content (HTML, CSS, JavaScript) for display to the user.
Key Functions:
- Rendering HTML and other web technologies to display pages.
- Storing bookmarks/favourites for quick access to frequently visited pages.
- Recording user history of visited pages.
- Allowing multiple tabs to be open simultaneously.
- Storing and managing cookies.
- Providing navigation tools (back, forward, refresh, home buttons).
- Offering an address bar for entering URLs.
- Supporting security features such as pop-up blocking, phishing alerts, and privacy modes.

When a user enters a URL into the browser:

Browser parses the URL to identify the protocol, domain, and path.
DNS (Domain Name Server) is queried to translate the domain name (e.g., www.example.com) into an IP address.
Browser sends a request (HTTP or HTTPS) to the web server hosting the site.
Web server processes the request and sends back the requested files (HTML, CSS, JavaScript, images).
Browser interprets the files and renders the page for display to the user.

Cookies are small text files stored on the user’s device by the web browser.
They are sent by the web server and can be retrieved by the server during subsequent visits.

Types of Cookies:

Session Cookies
- Temporary; stored only for the duration of the browsing session.
- Deleted once the browser is closed.
- Often used for keeping users logged in during a session or maintaining a shopping cart in an online store.
Persistent Cookies
- Stored on the user’s device for a set period (could be days, months, or years).
- Used for remembering user preferences, saved logins, or personalisation.

Uses of Cookies:

Privacy Considerations: