HTML & XHTML: The Definitive Guide, 6th Edition

HTML and XHTML: What They Aren't

Despite all their new, multimedia-enabling page-layout features, and the hot technologies that give life to HTML/XHTML documents over the Internet, it is also important to understand the languages' limitations. They are not word processing tools, desktop publishing solutions, or even programming languages. Their fundamental purpose is to define the structure of documents and document families so that they may be delivered quickly and easily to a user over a network for rendering on a variety of display devices; jacks-of-all-trades but masters of none, so to speak.

Content Versus Appearance

HTML and its progeny, XHTML, provide many different ways to let you define the appearance of your documents, but their focus is on structure, not appearance. Of course, appearance is important, since it can have either detrimental or beneficial effects on how users access and use the information in your documents. And that is why the companion CSS standard is important.

Nonetheless, we believe that content is paramount; appearance is secondary, particularly since it is less predictable, given the variety of browser graphics and text-formatting capabilities. In fact, HTML and XHTML contain many ways for structuring your document content without regard to the final appearance: section headers, structured lists, paragraphs, rules, titles, and embedded images are defined by the standard languages without regard for how these elements might be rendered by a browser. Consider, ...