What is XML?

XML stands for eXtensible Markup Language. It is a difficult language to describe because its applications lie within all corners of the broad computer science spectrum. Some describe XML as the same as HTML, but you make your own tags. This is half true, in that the syntax of HTML and XML are more or less the same, but the applications of XML go far beyond the web.

XML and HTML are both subsets of a larger language, called SGML. SGML stands for Standard Generalized Markup Language. The idea behind SGML, and all markup languages for that matter, is to divide data into its meaningful parts, whether that data is a web page, a newspaper article, or a whole book. By dividing data into meaningful parts, an application can understand the data easily.

XML is separated from HTML and other markup languages because it is extensible. This means that different applications can use the same data, whereas with other markup languages the data is meant for one application only. For instance, with HTML, the only application it is used for is the World Wide Web. In other words, XML is the embodiment of the separation of content from style.

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