Web and Internet Essentials

Internet

A global network of interconnected computers that communicate using the TCP/IP protocol. It allows devices around the world to share data, communicate, and access resources.

  • Works as the backbone of all online communication.
  • Enables access to services like the Web, Email, Cloud, etc.
  • TCP (Transmission Control Protocol/IP (Internet Protocol) is the system that lets devices communicate over the internet by breaking data into packets, sending them to the right address, and reassembling them correctly.

World Wide Web (WWW or Web)

The Web is an information system built on top of the internet, where data is presented as web pages that are interconnected via hyperlinks.

  • Not the same as the Internet — it's one of the services on the internet.
  • Uses HTTP/HTTPS protocol for communication.
  • Consists of documents written in HTML, styled with CSS, and enhanced with JavaScript.
  • Accessed via URLs (Uniform Resource Locator).

Web Browser

A software application that allows users to view and interact with web content/pages stored on the web.

  • Examples: Google Chrome, Mozilla Firefox, Safari, Microsoft Edge.
  • Interprets and renders HTML, CSS, and JS to display websites.
  • Communicates with web servers to fetch pages.

Website

A collection of web pages that are interconnected via hyperlinks, all under a common domain name.

  • Hosted on servers.
  • Accessible over the internet through a web browser using a URL.

Client & Server Architecture

Client

  • Any computer or device that sends request to a server and receives data (e.g., a web browser).
  • Requests web pages and displays content to users.

Server

  • A server is a powerful computer that stores and manages data (like websites, files, or applications).
  • It runs 24/7 and provides information to users when requested.

Domain & Hosting

Domain

  • The readable address or URL of a website (e.g., google.com) translated to an IP address via DNS.
  • Works as the website’s identity for users to find it easily.

Hosting

  • Hosting is a service that gives space on a server to store your website files.
  • It makes sure your website is accessible online through the internet 24/7.

Types of Websites

Static Website

  • Displays fixed content, same for all users.
  • Built only with HTML and CSS.
  • No interaction or database involved.
  • Example: Portfolio website.

Dynamic Website

  • Content changes based on user input or data.
  • Uses server-side logic and databases.
  • Example: E-commerce sites, social networks.

Frontend vs Backend

Frontend

  • User interface and experience
  • Built with HTML, CSS, JavaScript
  • Runs in the browser
  • Direct user interaction

Backend

  • Server-side logic and data handling
  • Built with Node.js, PHP, Python etc.
  • Runs on the server
  • Manages databases, APIs, services

Software

Software is a collection of instructions, data or computer programs that are used to run machines and carry out particualr activities.

System software

  • Designed to manage the resources of the computer system.
  • Less interactive for the users.

Application based software

  • Designed to fulfill the requirements of the user for performing specific tasks.
  • More interactive for the users.
  • Needs system software to run.
  • Desktop Application - Installed on computer and run locally.
  • Web Application - Accessed via a web browser over the internet.
  • Mobile Application - Installed directly onto a mobile device and run locally.

Summary

Internet Global interconnected network of computers.
Web Information system running on the Internet.
Browser Software to access and view websites.
Website Web pages stored on web linked via hyperlinks.
Software Computer programs to run a specific task.
Server Provides data/resources to clients.
Client Requests and receives data from server.
Domain Human-readable website address (URL).
Hosting Service storing and serving website files.

বাংলা নোটের জন্য এখানে ক্লিক করো।