Changing Text Appearance and Meaning
A number of tags change the appearance of and associate hidden meaning with text. In general, these tags can be grouped into two flavors: content-based styles and physical styles.
In addition, the World Wide Web Consortium (W3C) standard for Cascading Style Sheets (CSS) is now well supported by the popular browsers, providing another, more comprehensive way for authors to control the look and layout of their document text. We describe the tag-based text styles in this chapter. See Chapter 8 for details about CSS.
Content-Based Styles
Content-based style tags inform the browser that the enclosed text has a specific meaning, context, or usage. The browser then formats the text in a manner consistent with that meaning, context, or usage. Note the distinction here. Content-based style tags confer meaning, not formatting. Accordingly, they are important for automated processes; machines don't care what the document looks like—at least for now.
Because font style is specified via semantic clues, the browser can choose a display style that is appropriate for the user. Because such styles vary by locale, using content-based styles helps ensure that your documents will have meaning to a broader range of readers. This is particularly important when a browser is targeted at blind or handicapped readers whose display options are radically different from conventional text or are extremely limited in some way.
The current HTML and XHTML standards do not define ...