XML = eXtensible Markup Language |
XML is a subset of SGML -- Standard Generalized Markup Language, but unlike the latter, XML is specifically designed for the web |
XML is used to define logical document structure |
XML is not backward compatible with HTML, but the two coexist quite elegantly |
XML can be thought of as an ASCII version of a database |
XML can be used as an object IDL to access databases or any objects and so give web HTML templates to access web-linked databases / backend services |
XML can be used as inter object data (serialization) format for any object model |
XHTML is HTML4 written in XML syntax |