1.3 Introducing HTML, XHTML, and CSS
This one is a bit fragmented. I am trying to explain what HTML, XHTML, and CSS are. However, this section has mostly become a list of facts that I have failed to smoothly transition between the points I am trying to make.
1. What is HTML
2. What is XHTML
3. Why companies are bad and standards are good
4. How CSS plays a part in separating logical structure from appearance
Thanks for your feedback.
Introducing HTML, XHTML, and CSS
The Hypertext Markup Language, or HTML, is a markup language used to create web pages incorporating hyperlinks and media such as text, graphics, sound, video, and games. A markup language is a system for indicating the logical structure of a document, such as paragraphs and headings. The HTML language is derived from the Standard Generalized Markup Language (SGML). The SGML language is quite complex and thus is limited to organizations that can afford the cost of maintaining SGML systems. However, SGML is general enough to describe other markup languages, one of which is HTML.
The Extensible Hypertext Markup Language, or XHTML, has been designed to appear very similar to HTML. However, the XHTML language is not derived from SGML, but instead derived from the Extensible Markup Language. This language indicates not only a document's logical structure, but also how a document is to be displayed. One of the many differences between HTML and XHTML is that XHTML is case-sensitive, meaning upper and lower case letters are considered unique, whereas HTML is case-insensitive, meaning upper and lower case letters are considered equal. This book will detail the many differences between HTML and XHTML and let you decide what language you want to use.
The HTML language has mutated many times since its arrival. For several years following the creation of HTML, there was no organization responsible for maintaining the HTML standard. The competing browser companies added many extensions to the HTML language. Their work mostly soiled the purpose of the language, which is to provide the means to indicate the logical structure of a document without indicating how the document is to be displayed. The blame lies mostly with the developers of Internet Explorer and Netscape Navigator. The extensions they created provided many features, such as marquee-style text and background audio, but made HTML code non-portable. A web page that incorporated extensions, might have worked in one browser but not another.
Thankfully, an organization stepped in and has since been telling browser developers what HTML is, making it their loss if they try to branch from the standard. This organization is the World Wide Web Consortium (W3C) and is responsible for the long-term growth of the web. The members draft, circulate, and modify standards for various web technologies based on user feedback, to best fill the needs of the community. The W3C has separated the logical structure of a document from the appearance of a document by creating Cascading Style Sheets (CSS) created specifically to detail the appearance of a document. The W3C creates and manages the HTML, XHTML, and CSS standards.