Web Essentials: How the Web Works

Client

• A client is a device (computer or phone) that sends requests to a server.
• Web browsers (Chrome, Firefox, Safari) are common clients.

Server

• A server is a computer that stores web pages, data, or services.
• It listens for client requests and responds with content.

Client and Server Communication

• Client sends a request to the server.
• Server sends a response back.
• Communication often uses HTTP.

Internet

• A global network of interconnected computers.
• Connects billions of devices and allows data sharing.
• Made up of routers, switches, and physical cables (fiber optics).
• Uses protocols like TCP/IP to transfer data reliably.

World Wide Web

• A collection of web pages and resources accessible via the Internet.
• Created by Tim Berners-Lee in 1989.
• Web pages are built using HTML, styled with CSS, and made interactive with JavaScript.

HTTP (Hypertext Transfer Protocol)

• A protocol for transferring web pages over the Internet.
• Defines how messages are formatted and transmitted.
• Client sends an HTTP request to a server, which processes it, and sends back an HTTP response.

HTTP Request

• Example:
  • HTTP Method: GET /index.html HTTP/1.1
  • Host: www.example.com

HTTPS

• HTTPS = HTTP + SSL/TLS encryption.
• Keeps data secure.