Unit 11: Internet
Contents
1. Basic Internet Terminology
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite (TCP/IP) to link several billion devices worldwide.
- Web Page: A document, typically written in HTML, that is viewable in a web browser.
- Website: A collection of related web pages identified by a common domain name.
- Home Page: The introductory or main page of a website.
- URL (Uniform Resource Locator): The global address used to locate resources on the World Wide Web.
- ISP (Internet Service Provider): An organization that provides services for accessing and using the Internet.
- Hypertext: Text displayed on a computer that contains links to other text that the reader can immediately access.
2. Web Browser and its Environment
A Web Browser is a software application used to access information on the World Wide Web. When a user requests a web page from a particular website, the web browser retrieves the necessary content from a Web Server and then displays the page on the user's device.
Common Technologies:
- HTML (HyperText Markup Language): The standard markup language for creating web pages.
- DHTML (Dynamic HTML): A collection of technologies used together to create interactive and animated websites.
- XML (eXtensible Markup Language): A markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable.
3. Client-Side and Server-Side Scripting
Scripting languages are used to add functionality and interactivity to web pages. They are categorized based on where the code is executed.
| Feature | Client-Side Scripting | Server-Side Scripting |
|---|---|---|
| Execution | Executed in the user's web browser. | Executed on the web server. |
| Focus | User interface and interactivity. | Database access and business logic. |
| Examples | JavaScript, VBScript. | PHP, Python, Ruby on Rails. |
4. Internet Applications
The Internet supports a wide variety of applications that facilitate communication and information exchange.
- WWW (World Wide Web): A system of interlinked hypertext documents accessed via the Internet.
- E-mail: A method of exchanging messages between people using electronic devices.
- Instant Messaging: Real-time text transmission over the Internet.
- Internet Telephony (VoIP): The delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks.
- Videoconferencing: Conducting a conference between two or more participants at different sites by using computer networks to transmit audio and video data.
5. Exam Focus Enhancements
- URL Anatomy: Be prepared to label parts of a URL (e.g., protocol, domain, path).
- WWW vs. Internet: Remember that the Internet is the hardware network, while the WWW is one service that runs on it.
- Scripting Difference: Clearly explain that Client-side is for the "front-end" and Server-side is for the "back-end."
- Confusing Web Page with Website. A page is a single document; a site is the whole book.
- Thinking ISP and Web Server are the same. Your ISP gives you a pipe to the internet; the server holds the content.
Q: What does a Web Server do?
A: It is a computer that stores web files and delivers them to users via the internet when requested through a browser.
Q: Why is HTML called a 'Markup' language?
A: Because it uses 'tags' to 'mark up' or annotate the text so the browser knows how to display it.