Many of today??™s user agents (types of devices) look for their speci
?¬? c type of style sheet. For example, smartphones such as RIM??™s
Blackberrry and Palm??™s Treo look for a style sheet de?¬? ned for use by
a handheld device??”and if it is present, use it, thus enabling you to
provide a modi?¬? ed or entirely different presentation of the same
XHTML on these small-screen devices.
Each style sheet causes the content to be presented in the best
possible way for that use, but you only ever need one version of
the XHTML content markup. As you will see, an XHTML page
can automatically select the correct style sheet for each device or
environment in which it is displayed. In this way, your write-once,
use-many content becomes truly portable, ?¬‚ exible, and ready for
whatever presentational requirements the future may bring its way.
Note, however, that like any great vision of the future, there are still
some current realities that we need to deal with.
XHTML and How To Write It
Because CSS is a mechanism for styling XHTML, you can??™t start
using CSS until you have a solid grounding in XHTML. And what,
exactly, is XHTML? XHTML is a reformulation of HTML as XML??”
didja get that? Put (very) simply, XHTML is based on the free-form
structure of XML, where tags can be named to actually describe the
content they contain; for example,
Madonna.
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