Chapter 2: Building Your First Web Page: HTML Basics
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Figure 2-15: Use horizontal rules to help divide your Web pages into easy-to-read sections.
Introducing XHTML One of the biggest recent changes in the world of HTML is the emergence of XML, the eXstensible Markup Language. Because it allows site designers to designate what things are (for example, album titles, book publication dates, and other database-field-like identifiers), rather than how to present them (that is, italics, bold, green text), XML looks vaguely like HTML; but it is a completely different beast. Fortunately, you don’t have to worry about XML in this book! One way that XML has influenced HTML is through the growth of XHTML, a variation of HTML inspired by the formal structure of XML. The best way to think about XHTML is that it’s a for malized version of HTML. Gone are the sloppy mixed case tags of yesteryear and the random differences between tag usage. Instead, XHTML insists that • All tags are paired or have a /> ending. • All attributes are quoted. • All attributes must be presented as name=value pairs. • All tags and attributes must be in lowercase only.