XML stands for Extensible Markup Language and is a language used for describing data. Moreover, XML was not designed to do anything. Instead, it is used by other languages to structure, store, and exchange data. The markup tags in XML are not predefined as they are in HTML. This is why it’s called an extensible language, because you can create your own markup tags. By defining valid tags and semantic – either using a document type definition (DTD) or its successor the XML Schema – it’s possible to create new languages with XML. Some examples of languages specified in XML are: XHTML, SOAP, and RSS.
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