SGML, for Standard Generalized Markup Language, is ISO Standard 8879. SGML has a record of successful application in large, complex, sophisticated, publishing applications. However, it had never (as of mid-1996) really taken off on the World-Wide Web, despite the fact that HTML was advertised as being an application of SGML.
XML is an attempt to package up the important virtues and most-used features of SGML in a compact, easily-implemented package that is optimized for delivery on the WWW.
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