World Wide Web

Definition

The World Wide Web (WWW), often referred to as the Web, is an information system where documents and other web resources are identified by Uniform Resource Locators (URLs), interconnected by hypertext links, and accessible via the Internet. It acts as a vast collection of interlinked pages that users navigate using a web browser.

Main Content

1. Hypertext Transfer Protocol (HTTP)

• HTTP is the foundation of data communication for the World Wide Web. It defines how messages are formatted and transmitted between web servers and browsers.
• It acts as a request-response protocol; for example, a browser sends an "HTTP GET" request to a server to fetch a specific webpage.

2. Uniform Resource Locator (URL)

• A URL is the unique address used to locate a resource on the web, commonly known as a web address.
• It consists of components like the protocol (https://), the domain name (www.example.com), and the specific path to a file or page.

3. Hypertext Markup Language (HTML)

• HTML is the standard markup language used to create the structure and content of web pages.
• It uses "tags" (like <h1>, <p>, <a>) to define elements such as headings, paragraphs, and links, which the browser interprets to display the page visually.

Working / Process

1. Request Initiation

• When a user enters a URL into a web browser, the browser breaks down the address to identify the server's IP address using the Domain Name System (DNS).
• The browser then initiates an HTTP request to that specific server to retrieve the requested content.

2. Server Processing

• The web server receives the request and searches for the corresponding file (usually an HTML file or a dynamic script).
• Once located, the server packages the content and sends it back to the client along with an HTTP status code (e.g., 200 OK for success).

3. Rendering the Page

• The web browser receives the HTML data and begins parsing the code to build the Document Object Model (DOM).
• The browser then fetches additional assets like CSS (for design) and JavaScript (for interactivity) to render the final visual layout for the user.

[User] <----(Request)----> [Internet/DNS] <----(Request/Response)----> [Web Server]
  |                                                                        |
  +---(Rendered Result) <--------------------------------------------------+

(Visualization of the Request-Response cycle between a user and a server)

Advantages / Applications

• Global Accessibility: The Web allows users to access information, services, and communication tools from anywhere in the world at any time.
• E-Commerce and Education: It has revolutionized industries by enabling online shopping (Amazon) and remote learning platforms (Coursera/Canvas), making resources scalable and widely available.
• Interconnectivity: Through hyperlinks, the Web creates a massive, non-linear network of information, allowing users to jump between related topics seamlessly.

Summary

The World Wide Web is a global digital information space built on the infrastructure of the Internet, utilizing protocols like HTTP and languages like HTML to link and display content. It serves as the primary interface through which modern society consumes data, conducts business, and interacts with global services.

• Key point: The Web is not the same as the Internet; the Internet is the physical network, and the Web is the service built on top of it.
• Key point: Communication relies on the client-server model where browsers request data and servers deliver it.
• Key point: Web development revolves around the trio of HTML (structure), CSS (style), and JavaScript (behavior).
• Important terms to remember: HTTP, URL, HTML, DNS, Web Server, Browser.