Smart Solution

HTML has progressed through a number of versions since its inception. The latest
standard is version 4.01, which was released by the W3C in late 1999. This is the last
release of HTML in its current state. The next generation of HTML is called the
Extensible Hypertext Markup Language (XHTML).The W3C released version 1.0

of XHTML in January 2000; a revised version was released in August 2002. As defined
in the W3C XHTML recommendation (www.w3.org/TR/xhtml1/), there are three
“flavors” of XHTML:

• XHTML Strict—Use this when you want clean structural markup code, free
  of any markup tags associated with layout. Use XHTML Strict with
  Cascading Style Sheets to get the font, color, and layout effects you want. If
  you are beginning a new Web site, you should code to this recommendation.
• XHTML Transitional—This type of XHTML is designed for people writing Web
  pages for the general public.The idea is to take advantage of XHTML features,
  including style sheets, but make small adjustments to your markup code for those
  viewing your pages with older browsers, which can’t understand style sheets.
• XHTML Frameset—Use this when you want to use frames to partition the
  browser window into two or more sections.You can learn more about frames
  by reading the “Working with Frames” chapter on the Online Companion
  Web site for this book.

How do these three types of XHTML affect you as a Web developer? Your goal should
be to create code that matches the strict recommendation, using Cascading Style Sheets
for all of your display information. The benefit of the transitional type is that it allows
you to gradually migrate from existing HTML code that may still contain font and display
information to the more syntactically correct, cleaner markup code necessary to match
the strict type.

The frameset specification is important only if you plan to use frames to
partition the browser window, as described in the “Working with Frames” chapter posted
on the Online Companion Web site for this book.