HTML Course 1.1: What is the Internet and the World Wide Web?

In order to build rich, interactive websites, it’s essential to understand the difference between the Internet and the World Wide Web. While the two terms are often used interchangeably, they refer to distinct concepts:

1. The Internet

The Internet is a massive global network of interconnected computers and devices. It provides the physical and logical infrastructure that allows data to flow from one point to another. Key characteristics include:

Global Network of Networks: Millions of private, public and academic networks.
Layered Protocol Stack: Follows the TCP/IP model to standardize communication.
Fundamental Protocols:
- IP (Internet Protocol) – addressing and routing packets.
- TCP (Transmission Control Protocol) – reliable connection and data ordering.
- UDP (User Datagram Protocol) – low-latency, connectionless transmission.
Supporting Services: DNS (Domain Name System), email (SMTP/IMAP/POP3), file transfer (FTP), remote login (SSH), and more.

TCP/IP Model Layers

Layer	Function	Example Protocols
Application	User-facing services and applications	HTTP, FTP, SMTP, DNS
Transport	End-to-end communication and reliability	TCP, UDP
Internet	Routing and addressing	IP, ICMP
Link	Physical data transfer on the local network	Ethernet, Wi-Fi, ARP

2. The World Wide Web (WWW)

The World Wide Web is a service built on top of the Internet. It consists of interconnected documents and resources, linked by hyperlinks and identified by URLs. Core components:

HTTP/HTTPS: Protocols for transferring HTML documents, images, scripts.
HTML: Markup language that structures the content of web pages.
Browsers: Client applications (Chrome, Firefox, Safari) that render HTML, CSS, and JavaScript.
URIs/URLs: Addresses that locate web resources.

URL Breakdown

Scheme: Defines the protocol (e.g., http:// or https://).
Host: Domain name or IP address (e.g., www.example.com).
Port: Optional numeric port (defaults to 80 for HTTP, 443 for HTTPS).
Path: Resource path on the server (e.g., /articles/index.html).
Query: Parameters sent to the server (e.g., ?id=123&ref=home).
Fragment: In-page anchor (e.g., #section2).


https://www.example.com:443/articles/index.html?id=123&ref=home#section2

3. Internet vs. World Wide Web: Key Differences

Aspect	Internet	World Wide Web
Definition	Physical and logical network infrastructure	Collection of interconnected documents and services
Core Protocols	IP, TCP, UDP, DNS, ARP	HTTP/HTTPS, HTML, CSS, JavaScript
Requires	Routers, switches, cables, network interfaces	Web server, browser, HTML files, media
Function	Transports data globally	Presents and links information in hypertext form

4. How They Work Together

User enters a URL into the browser’s address bar.
Browser consults DNS to resolve www.example.com into an IP address.
TCP handshake establishes a connection to the server’s IP and port.
Browser sends an HTTP GET request for the resource.
Server responds with HTML, CSS, JavaScript and media assets.
Browser renders the HTML, applies CSS and executes JavaScript.
Links on the page may trigger new HTTP requests, repeating the cycle.

5. Simple HTML Example (the Web Side)

The HTML below is an example of a basic webpage delivered over the Internet via HTTP:

My First Webpage

Welcome to the World Wide Web

This page is delivered via HTTP over the Internet.

Visit Example.com

By mastering these foundational concepts, you’ll be well-equipped to understand how your HTML pages travel across the global Internet and appear in users’ browsers as part of the World Wide Web.

HTML Course 1.1 What is the Internet and the World Wide Web?