HTML and CSS Reference
1 Introduction to HTML,
XHTML, and CSS
Before diving into the details of creating Web pages with HTML5 and CSS, it is useful
to look at how these technologies relate to the development of the Internet and the
World Wide Web. The Internet began with the connection of computers and computer
networks. This connectivity has had a huge impact on our daily lives. Today, millions of
people worldwide have access to the Internet, the world's largest network. Billions of Web
pages, providing information on any subject you can imagine, are currently available on
the World Wide Web. People use the Internet to search for information, to communicate
with others around the world, and to seek entertainment. Students register for classes, pay
tuition, and find out final grades via this computer network. Stores and individuals sell
their products using computer connectivity, and most industries rely on the Internet and
the World Wide Web for business transactions.
Hypertext Markup Language (HTML) and more recently HTML5 and Cascading
Style Sheets (CSS) allow the World Wide Web to exist. In order to utilize these tech-
nologies effectively, you need to understand the main concepts behind the Internet and
HTML. In this chapter, you learn some basics about the Internet, the World Wide Web,
intranets, and extranets. You are introduced to Web browsers, definitions of HTML and
associated key terms, the five phases of the Web development life cycle, and the tasks that
are involved in each phase.
What Is the Internet?
Most people today have had exposure to the Internet at school, in their homes, at their jobs,
or at their local library. The Internet is a worldwide collection of computers and computer
networks that links billions of computers used by businesses, government, educational insti-
tutions, organizations, and individuals using modems, phone lines, television cables, satellite
links, fiber-optic connections, and other communications devices and media (Figure 1-1).
Figure 1-1 The Internet is a worldwide collection of computer networks.