body -- or chaotically imposed on the market by individual browser vendors -- new Extensible Markup Language tags can be created by anyone at any time. To prevent too much chaos, Extensible Markup Language tags used by a particular Extensible Markup Language application document can be described in a file called a “document type definition.” The DTD can reside in the same place as the Extensible Markup Language document or at any location on the Internet. By referring to the definition file, an Extensible Markup Language parser, or reader, can verify that the document is “valid.” Being “valid” means that the document is in compliance with both the Extensible Markup Language grammar and the rules of the newly created document type definition file. Also, other developers could refer to this document when generating other sites that need to communicate with the existing site.The Standardization ChallengeAs I mentioned earlier, the new Extensible Markup Language format generation creates challenges in the industry with regard to standardization. Sarah Robers, of Inter@ctive Week, explains:“Extensible Markup Language widespread implementation has met several hurdles, not the least being compatibility around the multitude Extensible Markup Language schemas or document-type definitions that have been cropping up. Much of the future success depends on vendors efforts to set the various language schemas, or standards. “What does she mean? Well, what you ultimately want is for two computers to talk to each other and to know what they are talking about. No problem there so far. Where the problem arises is that computer one may describe something to computer two, who “thinks” that computer one has introduced something new, when the reality is that it did not, it just referred to the item by a different name. The problem is how you define each component, whether it is a telephone number or...
