XML is the core language of the Web. It forms the foundation for nearly everything you read with your browser. You might not know this, though, because of the great number of languages and acronyms you find. Web pages are written in XHTML, news feeds are written in RSS, and many applications communicate to each other with XML-RPC. If you use Google Talk, then you are relying on the Jabber protocol. What do each of these languages have in common? They are all XML languages.
How is that possible? XML gives you a set of rules for defining new computer languages. Although nearly any sort of language can be created, XML is most appropriate for two tasks.
- Text formatting
- Data exchange
“Text formatting” is probably the most familiar to you. Many Web pages are formatted with XHTML - a cleaned-up version of HTML, which you may be more familiar with. XHTML provides structure to the documents, making them easily processed by Web browsers and specialized scripts. All the headers, paragraphs, lists and links are described in XHTML. A well-formed Web document can be printed, viewed in a monitor, or read out loud by a text-to-speech program. XML provides the rules which make it that much easier for your Web page to be considered well-formed.
Since XML is essentially the language of the Web, you will have no trouble finding helpful resources in getting familiar with XML.