F.1. Introduction

Welcome to the world of opportunity created by the World Wide Web. The Internet is now three decades old, but it was not until the Web became popular in the 1990s that the explosion of opportunity that we are still experiencing began. Exciting new developments occur almost dailythe pace of innovation is unprecedented by any other technology. In this chapter, you will develop your own Web pages. As the book proceeds, you will create increasingly appealing and powerful Web pages. In the later portion of the book, you will learn how to create complete Web-based applications.

This chapter begins unlocking the power of Web-based application development with XHTMLthe Extensible HyperText Markup Language. In later chapters, we introduce more sophisticated XHTML techniques, such as tables, which are particularly useful for structuring information from databases (i.e., software that stores structured sets of data), and Cascading Style Sheets (CSS), which make Web pages more visually appealing.

Unlike procedural programming languages such as C, Fortran, Cobol and Pascal, XHTML is a markup language that specifies the format of the text that is displayed in a Web browser such as Microsoft's Internet Explorer or Netscape.

One key issue when using XHTML is the separation of the presentation of a document (i.e., the document's appearance when rendered by a browser) from the structure of the document's information. XHTML is based on HTML (HyperText Markup Language)a legacy technology of the World Wide Web Consortium (W3C). In HTML, it was common to specify the document's content, structure and formatting. Formatting might specify where the browser placed an element in a Web page or the fonts and colors used to display an element. XHTML 1.1 (W3C's latest version of W3C XHTML Recommendation at the time of publication) allows only a document's content and structure to appear in a valid XHTML document, and not its formatting. Normally, such formatting is specified with Cascading Style Sheets (Chapter 6). All our examples in this chapter are based upon the XHTML 1.1 Recommendation.