SGML and HTML, XML

In the watch salad oil teacher's video, just started the first section, because it is not real-time live in some do not understand the timely question from a Baidu, excerpt as follows, about SGML (the following excerpt from Baidu Library):

SGML (Standard Universal Markup Language, commonly known as general purpose) is the ideal data storage format, providing a considerable number of options that can be applied to the most complex information processing ...

SGML is an international standard that ISO has developed in 1986 to describe the structure and content of document materials, and to achieve document exchange and sharing. It is the standard of data description, data modeling and data exchange, and it is also a meta language. Meta-language is a set of common rules that can be used to define other more specialized markup languages, and HTML is defined by SGML to be used exclusively on the WWW Markup language.

XML is the standard presented by the World Wide Web in the end of 1996, it is a simplified form derived from SGML, is also a meta-language, can be used to define any new markup language, XML is designed to complement the HTML is not perfect, so that the web can transfer, processing all kinds of complex files, As a core standard, XML provides a solid foundation for other standards that may arise.

SGML and HTML, XML