WEB SCIENCE NOTES

Introduction to Web Science

Definition

• Interdisciplinary field exploring the social and technical systems underlying the World Wide Web.
• Combines sociology, computer science, economics, and mathematics.

Significance

The web is a vast socio-technical construct and plays a critical role in human communication and information sharing.

Understanding Internet vs. Web

Internet

• Global network enabling data exchange and communication.
• Backbone for various services like email, file sharing, and VOIP.

World Wide Web

• A service on the Internet.
• Consists of hypertext-linked resources accessed using browsers.

Core Protocols and Standards

Protocols

• TCP/IP for communication.
• HTTP/S for accessing and transferring web resources securely.
• SMTP for emails and FTP for file transfers.

Standards

• Govern the correct use of HTML, CSS, XML, and JavaScript for compatibility and accessibility.

Web Evolution

• Web 1.0: Static, read-only pages with minimal interactivity.
• Web 2.0: Focuses on user-generated content, social interaction, and collaboration (blogs, wikis, social media).
• Web 3.0: Semantic web, enabling data to be interpreted by machines for smarter applications.

Web Development Technologies

• HTML (HyperText Markup Language): Core language for creating web pages. Provides structure using tags.
• CSS (Cascading Style Sheets): Enhances presentation and styling. Facilitates responsive and aesthetic design.
• JavaScript: Client-side scripting for interactive and dynamic content.
• PHP: Server-side scripting for backend processes like database interaction.
• XML: Formats data for easy storage, sharing, and manipulation.
• XSLT: Transforms XML data into other formats like HTML or plain text.

Static vs. Dynamic Web Pages

• Static Pages: Unchanging content, designed on the server-side. Example: Personal portfolios, informational websites.
• Dynamic Pages: Interactive and adaptable based on user input. Employ server-side scripting languages like PHP or client-side scripting like JavaScript.

Web Components

• URI, URL, URN:
  • URI: General identifier for a resource.
  • URL: Specifies the resource's location and retrieval method.
  • URN: Persistent identifier like an ISBN for books.
• Website Elements: Navigation bars, hyperlinks, banners, sidebars, and metadata.

Internet Infrastructure

• Data Transmission: Uses packets with headers and payloads for efficient delivery. IP protocol routes these packets to correct addresses.
• DNS: Converts human-readable domain names (e.g., google.com) to IP addresses.

Web Technologies and Applications

• Browsers: Render HTML, CSS, and JavaScript. Enable plugins for multimedia content.
• Web Applications: Interactive and data-driven (e.g., e-commerce platforms, social media). Operate both online and offline using technologies like HTML5.
• Client-Side vs. Server-Side Scripting:
  • Client-side: Enhances user experience via interactivity.
  • Server-side: Handles backend tasks like authentication and data retrieval.

Examples of Web Use Cases

• Personal Pages: Informational, often static, with minimal scripting.
• Blogs: Frequently updated, using dynamic content managers like WordPress.
• Search Engines: Leverage web crawlers and efficient algorithms.
• Forums and Wikis: Interactive platforms for collaboration and discussion.
• Learning Management Systems (LMS): Tools for e-learning with heavy client-side and server-side integration.

Web Protocols in Depth

• HTTP and HTTPS: Protocols for transferring data; HTTPS includes encryption via SSL/TLS. Supports methods like GET, POST, PUT, DELETE for interactions.
• FTP: Protocol for file exchange.
• DNS: Maps domain names to IP addresses.
• TCP/UDP: TCP ensures reliable data transfer; UDP prioritizes speed over reliability for applications like gaming.

Security and Accessibility

• Web Standards: Established by organizations like W3C and ISO for consistent development. Emphasize accessibility, interoperability, and semantic web practices.
• HTTPS: Secures data with encryption, digital certificates, and authentication.

Advanced Topics

• Semantic Web: Focuses on machine-readable data for advanced applications like AI.
• Web of Things: Connecting IoT devices via web protocols for seamless integration.
• Web APIs: Allow applications to interact with other services or platforms programmatically.