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The purpose of this chapter is to introduce you to the Hypertext Markup Language (HTML), the standard for Web pages.
HTML was devised as a method of representing complex documents, namely documents containing text; images; other media, such as sound, including types of media not invented at the time of the original specification of the language; and hyperlinks, that is, specifications of links from one document to another. Furthermore, the goal of the method was to provide a way to display such documents on any computer so that people—at that time, mainly scientists—could share information even though some might be using one type of computer with one operating system and others totally different computer hardware and/or different operating systems software. Tim Berners-Lee at CERN, the European Organization for Nuclear Research, and others (including Cailliau, Andreesen, and Bina) are credited with inventing HTML and the other technologies that support what is called the World Wide Web. The definition of HTML and other, related technologies, are maintained by an organization called the World Wide Web Consortium (W3C).
The following factors:
Support for mixed media and hyperlink
Design allowing a systematic way for the system to grow with new media types
Independence to any particular hardware/software platform
made the invention of the Web and HTML a tremendous achievement. However, technologies evolve, both in response to invention and demand. The original HTML did not specify the exact format for display. This would have been very difficult and maybe not even possible given that the intent was to provide for presentation of the documents on screens of vastly different sizes on computers with different capabilities. Instead, the designers included features to specify a more general, logical level of formatting.
Another perceived deficit of the original HTML is the main subject of this book. The design of HTML and the communication standards that support the Web do not provide facilities for customizing the documents based on information in databases or files. Moreover, the way operations work between the server computer and the client computer is that the server sends the files requested by the client and does not save information on the request. This is not quite true, since log files can be kept, but the Web is designed to be what is called “stateless,” and information on requests is not readily available. This would mean that collecting data for research or e-commerce would be impossible. To address this need, people developed and are still developing new standards and new products. After this chapter on basic HTML and the next chapter on forms and client-side scripting, you will learn about middleware, technologies to bridge the gap between Web pages and databases and other resources on the server.