Introduction of web technologies

What is Internet?

A Brief History

• The Internet originated in 1969 as a U.S. Defense Department experiment designed to create a network resilient enough to survive Cold War disruptions.
• Initially, it was known as ARPANET.
• As the network expanded, hundreds of universities and research institutions connected to ARPANET to collaborate and share information.
• By the late 1980s, ARPANET evolved and was renamed the Internet.
• For over 20 years, the Internet remained largely unnoticed by the general public and business sectors.
• In 1989, Tim Berners-Lee, a researcher at CERN in Europe, introduced the concept of the World Wide Web — a breakthrough that quickly propelled the Internet into mainstream popularity.

Who Makes up the Internet?

• Users – Individuals and organizations that access and use the Internet for various purposes.
• Service Providers – Companies that offer Internet access and related services to users (e.g., ISPs).
• Content Providers – Entities that create and share information, media, and services online.
• Infrastructure Companies – Firms that build and maintain the physical and network infrastructure (e.g., cables, data centers).
• Software & Hardware Companies – Developers and manufacturers of the tools needed to access and navigate the Internet.
• Governments – Play roles in regulation, policy-making, and cybersecurity.
• Internet Society – Organizations that help guide the Internet’s development and standards (e.g., ICANN, IETF).
• Colleges & Universities – Contribute through research, innovation, and providing network access for education and collaboration.

What is the Internet used for?

Uses of the Internet

• Fast Worldwide Communication – Through email, Skype, social media, messaging apps, and IoT-connected devices.
• Research – A massive resource for academic, professional, and personal knowledge.
• Software Downloading and Uploading – Access to applications, tools, and updates.
• News and Information – Instant access to global updates, articles, and media.
• E-commerce – Buying and selling products and services online.
• Streaming Media – Listening to live or recorded radio, watching TV shows, and movies from around the globe.
• Additional Uses:
  • Online Learning – Virtual classrooms, e-learning platforms, and digital libraries.
  • Remote Work – Telecommuting, cloud collaboration tools, and virtual meetings.
  • Banking & Finance – Online banking, stock trading, and financial planning.
  • Gaming – Online multiplayer games and downloadable entertainment.
  • Cloud Storage – Saving and accessing files from anywhere.

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How the Internet Works?

• A Global Network of Computers – A system connecting computers worldwide.
• Powerful Machines (Hosts/Servers) – These manage and distribute data, running 24/7 for reliability.
• High-Speed Communication – Computers exchange data using fast and reliable channels.
• Communication Media Include:
  • Copper or Fiber-Optic Cables – Physical wired connections for high-speed data transfer.
  • Microwaves via Satellite – Wireless, long-distance communication using satellites.
  • Point-to-Point Microwaves or Radio waves – Direct wireless signals between specific locations.

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Internet Vs Web

• The Internet is the physical network made up of millions of interconnected computers and networks around the world.
• The Web (World Wide Web) operates on top of the Internet, relying on it to function.
• The Web is made up of hypertext documents (Web pages) that are linked together and hosted on various websites.

Internet Service Provider (ISP)

• Internet Service Providers (ISPs) – These companies offer local access to the Internet backbone.
• Essential for Internet Access – You need an ISP to connect your device to the Internet.
• Subscription-Based – Users typically pay a monthly fee for this service.
• Examples – BT, Sky, Virgin, and other regional or global providers.

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Important Terms

• Hypertext is a method of organizing and presenting information that allows readers to choose their own reading path, rather than following a fixed sequence.
• Hyperlinks are clickable, underlined or highlighted words or images that lead to another document or web page.
• Hypermedia extends hypertext by including links to multimedia content, such as audio, video, and animations.
• The Web is a distributed hypermedia system, meaning content creation and management are shared across many individuals and organizations worldwide.

Uniform Resource Locator(URL)

• Web Addresses are part of an addressing system used to locate resources on the Web.
• The Uniform Resource Locator (URL) is the standard format for identifying and accessing these resources.
• A URL typically consists of the following components:
  1. Protocol – Specifies how the resource will be accessed (e.g., http://, https://, ftp://).
  2. Domain Name – The address of the server where the resource is hosted (e.g., www.example.com).
  3. Path – The specific location of the resource on the server (e.g., /folder/page.html).
  4. Optional Elements:
     • Port Number – Defines a specific communication endpoint (e.g., :8080).
     • Query String – Sends data to the server (e.g., ?search=books).
     • Fragment Identifier – Refers to a specific part of the page (e.g., #section1).

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DNS – Domains and Subdomains

• Most Internet hosts or servers use a Domain Name System (DNS) address, which represents their location using easy-to-remember words instead of numerical IP addresses.
• A domain name helps identify the organization or institution that owns the server. For example, a server operated by BT may have the domain name bt.com.
• Large organizations often use subdomains to organize content across multiple servers or departments. For instance, products.bt.com could point to a server dedicated to BT’s product offerings.

Internet Protocols

• Internet Protocols refer to the set of rules that govern how data is transmitted and communicated across the Internet.
• Different types of communication require different protocols to ensure smooth and effective data exchange.
• These protocols help reduce issues when computers communicate with one another.
• Here, we’ll focus on four key protocols:
  • HTTP (Hypertext Transfer Protocol) – The protocol used for transferring web pages and content across the web.
  • TCP (Transmission Control Protocol) – Ensures reliable, error-free communication between computers by breaking down data into packets and reassembling them.
  • IP (Internet Protocol) – Addresses and routes data packets to the correct destination across networks.
  • FTP (File Transfer Protocol) – Used for transferring files between computers over the Internet.

HyperText Transfer Protocol (HTTP)

• HTTP stands for HyperText Transfer Protocol, and it defines the process through which computers communicate over the World Wide Web.
• Although HTTP is simple in design, it plays a crucial role in the functioning of e-commerce and web communications.

Types of HTTP:

• Static HTTP:
  • Original HTTP – Standard, unsecured HTTP communication, such as http://www.learnaitech.com
  • Secured HTTPS – A more secure version of HTTP, using encryption to protect data (e.g., https://ibank.barclays.co.uk), often used for financial transactions or sensitive information.
• Dynamic HTTP:
  • GET HTTP – Used to retrieve data from a server. It is commonly seen in URLs like http://ipcis.com/database/search.asp?query=userquery. This method appends data to the URL.
  • POST HTTP – Used to send data to a server, such as when submitting a form. Unlike GET, POST data is sent in the body of the request and cannot be viewed in the URL, ensuring a higher level of security for sensitive information.

How to Know a Website is Secure:

• HTTPS – When a website uses HTTPS (HyperText Transfer Protocol Secure), it means that all communications between your browser and the server are encrypted, ensuring privacy and security.
• Security Certificate – HTTPS is supported by a mathematical certificate (SSL/TLS certificate) that is issued only to registered and verified companies with a good credit history.
• Slower Connection – The encryption process makes HTTPS connections slightly slower, as every communication is protected through secure encryption.
• Important Security Tip – You should never enter sensitive information, like your credit card details or banking login credentials, on a website unless you see HTTPS in the address bar. If the site does not have this secure connection, it may not be safe.

Internet Protocols: TCP and IP

• Transmission Control Protocol (TCP) – This protocol sets the rules for how computers communicate and reliably exchange data over the Internet. It ensures that data is delivered accurately and in the correct order.
• Internet Protocol (IP) – This protocol defines how devices are identified on the Internet using a unique address system.
  • IP Address – Every device connected to the Internet is assigned a unique numerical address, known as an IP address.
    • Example: 209.234.456.8 (Note: this is a fictional example; real IP addresses have a valid format).

File Transfer Protocol (FTP)

• FTP (File Transfer Protocol) is a system used on the Internet that allows computers (clients) to transfer files to and from servers.
• Downloading refers to transferring files from an FTP server to a client’s computer.
• Uploading means sending files from a client’s computer to an FTP server.
• Clients can also store files on an FTP server, making them accessible from other devices or locations.

Intranets and Extranets

• Intranet – A private internal network used within a company or organization.
  – Functions similarly to the Internet but is restricted to internal users only.
  – Not accessible to individuals outside the organization.
  – Commonly used by companies and even some governments to manage internal communication and data.
  – Protected by a firewall, which acts as a security filter to monitor and control incoming and outgoing data.
• Extranet – An extension of an intranet that allows limited access to external users, such as partners, suppliers, or clients, through the Internet.

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Internet Browsers

• Internet browsers are software applications used to locate, access, and display web pages on a user’s device.
• They are essential for rendering web pages in a visual and user-friendly format.

Early Browsers:

• Could only display text and hyperlinks, with no support for images or multimedia content.

Modern Browsers:

• Support graphics, videos, and interactive plugins, enhancing the user experience with rich media content.

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Static vs. Dynamic Web Pages

• Static Websites consist of fixed content that does not change or interact with the user.
  – Think of them like printed pages in a book — you can read the content and navigate between pages, but you cannot interact with it.
• Dynamic Web Applications are interactive websites that respond to user input and often connect to databases or other programs.
  – These pages can process commercial transactions, remember user preferences, and allow functions like sending and receiving messages.

Examples of Static Web Pages:

• Common examples include basic homepages, news articles, and websites for small businesses with limited interactivity.

Examples of Dynamic Web Pages:

• Includes web-based email, online shopping platforms, and any site requiring user login or personalized interaction.

Technically the difference is:

Static vs Dynamic Web Pages: How They’re Updated & Programmed

• Static Web Pages store all the content directly within the page’s code.
  – Updating these pages requires manually editing and re-publishing the HTML file.
  – This process can be time-consuming, especially for websites with lots of content.
• Dynamic Web Pages store their content in a database.
  – Updating is easier—you simply log in to a system (like a CMS) and change the content.
  – The updated data is saved in the database and is automatically displayed to users in real-time.

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Programming Languages & Tools

Static Web Programming:

• Languages Used:
  • HTML (HyperText Markup Language)
• Tools and Editors:
  • Notepad++
  • Microsoft Word (saved as .html)
  • Adobe Dreamweaver
  • Many other basic or advanced text editors

Dynamic Web Programming:

• Languages Used:
  • ASP (Active Server Pages)
  • PHP (Hypertext Preprocessor)
  • JSP (Java Server Pages)
  • XML (Extensible Markup Language) (used for data storage and structure)

These languages enable the creation of interactive, data-driven websites where content can be easily managed and updated.

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Anchors (Hyperlinks)

An anchor is a hyperlink that connects to another webpage or location within a website. It allows users to navigate through different sections or pages easily.

Types of Anchors:

1. Standard Link – A basic link that takes the user from one webpage to another.
2. Internal Link – Directs the user to a specific section within the same page.
3. Parameterized Link – Includes variables or data to be processed by a server or database.
   • Example:
     www.ipcis.com/Database/St_Log.asp?Login=guest&Password=IPCIS
     (This sends login credentials to a server-side script.)

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HTML Forms

An HTML Form is a component of a webpage that collects user input.
Forms are a defining feature of dynamic websites, allowing interaction between the user and the server.

Common Uses of Forms:

• Collecting feedback
• Searching through databases
• Submitting personal or login information
• Placing orders in e-commerce platforms

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Communication Between a Form and a Server

Response is sent back to the user’s browser (confirmation, redirect, or error message).

User fills in the form fields.

Form is submitted using a button (usually labeled “Submit” or similar).

Data is sent to a web server, often via HTTP POST or GET methods.

Server processes the data, performs actions like saving to a database or checking credentials.

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Cookies and Session Management

• Cookies are small strings of text data stored in a file on the user’s computer, sent by a scripted web page.
• They allow web servers to recognize and differentiate between users during multiple visits.
• Cookies help web applications to personalize content and features based on each user’s preferences or previous activity.
  – For example, remembering login info, keeping items in a shopping cart, or saving language settings.

How do cookies work:

– Customer registers at a website.
– The website leaves a small file in the customer’s computer.
– This file is accessed whenever the customer visits that website again.
– Each cookie has an expiry day, if you don’t access that website for so much time, the cookie is deleted automatically by the browser.

Here’s the text again:

Importance of cookies:

– Customize the views for customers.
– Keep track of customers’ orders.
– Improve security through session management, such as when a session expires.

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Scripts (JavaScript vs Visual Basic Scripts)
• A script is a small piece of program embedded in a web page or sent as a separate file.
• A script is interpreted by its respective ‘interpreter’ in the order it appears in an HTML page.
• There are two types of scripts:
– Client-side scripts (attached to the page)
– Server-side scripts (stay on the server)

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Web Animation
• There are people who support and oppose using web animations.

Those supporting it:
– It’s good design.
– It can enhance the interface.
– An animation is worth a thousand pictures!

Those against it:
– Distracting.
– Only interesting the first time!

Types of animations:
– Image animation.
– Button animation.
– Whole page animation.

Examples:
– Adobe Flash (animation).
– Adobe Fireworks (graphics).

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