HTML and CSS Reference
Understanding Domain Names
The server name portion of a URL is also called the domain name . By studying a domain
name, you learn about the server hosting the Web site. Each domain name contains a
hierarchy of names separated by periods (.), with the top level appearing at the end. The
top level, called an extension , indicates the general audience supported by the Web
server. For example, . edu is the extension reserved for educational institutions, . gov is
used for agencies of the United States government, and . com is used for commercial
sites or general-use sites.
The next lower level appearing before the extension displays the name of the individ-
ual or organization hosting the site. The domain name camshots.com indicates a commer-
cial or general-use site owned by CAMshots. To avoid duplicating domain names, the top
two levels of the domain must be registered with the IANA (Internet Assigned Numbers
Authority) before they can be used. You can usually register your domain name through
your Web host. Be aware that you must pay an annual fee to keep a domain name.
The lowest levels of the domain, which appear farthest to the left in the domain name,
are assigned by the individual or company hosting the site. Large Web sites involving
hundreds of pages typically divide their domain names into several levels. For example,
a large company like Microsoft might have one domain name for file downloads—
downloads.microsoft.com —and another for customer service— service.microsoft.com .
Finally, the first part of the domain name displays the name of the hard drive or resource
storing the Web site files. Many companies have standardized on www as the initial part
of their domain names.
Gerry has listed four Web pages that he wants his readers to be able to access. He's
also provided you with the URLs for these pages, which are shown in Figure 2-38.
Popular Photography and Imaging
You'll link the names of the Web sites that Gerry has listed in the Tips page to the
URLs listed in Figure 2-38. For example, to link the text Apogee Photo to the Apogee
Photo Web site, you would use the following <a> tag:
<a href=” http://www.apogeephoto.com”>Ap ogee Photo</a>