Internet – Overview

Although the Internet is, quite simply, a network of networks, many design principles and specialized protocols are involved to make it all work. One design principle is that the Internet is a distributed system, rather than a centralized system. This is important as more devices get connected to the network. No part of the Internet is thus  “central”, meaning that there is no part of the overall network that, if it stops working, will shut down the entire Internet. The posts in this section provide introduction about how the Internet works and common technologies for designing web-based applications as well as the common misconceptions and challenges students have when using these technologies.

  • Internet – Introduction
    • We give a brief introduction to how the Internet works–i.e. its design and implementation, how data is transmitted digitally using analog signals, and what kinds of protocols are important. We provide links to several informative videos from, and we also include a brief description about a Project Loon which attempts to bring Internet access to the whole world by launching balloons into the stratosphere.
  • Internet – HTML (with video)
    • HTML, HyperText Markup Language, is the basic markup language that has defined web pages since the World Wide Web first began. HTML is an evolving language that has undergone significant changes  and continues to change as we move toward HTML5 as the new standard. This post gives an introduction about how to create basic HTML pages.
  • Internet – CSS  (with video)
    • Cascading Style Sheets (CSS) is a way to control the presentational elements of web pages. This posts illustrates how to use CSS for adding style (e.g., fonts, colors, spacing) to HTML documents.
  • Internet – Javascript (with video)
    • This post introduces how to use Javascript, a standard client-side scripting language that works with HTML and CSS, to create interactive web pages.
  • Internet – PHP (with video)
    • PHP is a popular server-side scripting language that is used to create dynamic web page content.  This post briefly introduce PHP as a way to add interactivity to web pages.
  • Internet – Student Misconceptions and Challenges
    • This post explains common misconceptions and challenges students have when using HTML, CSS, JavaScript, and PHP.