Mark-up
There are a lot of mark-up languages out there, from early ones such as SGML (an international standard in 1986) to the latest specialised ones derived from XML. They originate from printing and proof-reading, rather than programming languages.
SGML (Standard Generalized Markup Language) is a metalanguage - it defines how to create a good descriptive markup language, for example how to write tags and how to define the structure of the language.
Many people will be familiar with HTML (HyperText Markup Language), which has been used to create millions of web pages. The last standard was HTML 4.01. This was reformulated as XHTML 1.0 (EXtensible HyperText Markup Language) which became a standard in January 2000.
Whereas HTML concentrated on the display of data, and how it looked, XML (EXtensible Markup Language) concentrates on describing the data and its nature. XML can itself be used to create makeup for a wide variety of types of information. For example:
| AML | Astronomical Markup Language |
| CML | Chemical Markup Language |
| MathML | Mathematical Markup Language |
| SMIL | Synchronous Multimedia Integration Language, for multimedia presentations |
| VoiceXML | For speech |
| WML | Wireless Markup Language, for mobile phones |
XML is also associated with a variety of other components which may be needed to produce the required output, for example:
| CSS | Cascading Stylesheets * |
| DSSSL | Document Style Semantics and Specification Language * |
| DTD | Document Type Definition |
| RDF | Resource Description Framework |
| RSS | Formats for syndicating news and the content of news-like sites |
| SOAP | Simple Object Access Protocol. An XML based object protocol for the exchange of information in a decentralized, distributed environment |
| Topic Maps | Used to create an index of information which resides outside that information |
| Web Services | Self-contained, self-describing, modular applications that can be published, located, and invoked across the Web |
| XForms | Model for Web forms |
| XLink | XML Linking Language |
| XML Schema | XML Schema Definition Language |
| XPath | XML Path Language. The common layer between XSLT and XPointer |
| XPointer | XML Pointer Language |
| XQuery | Query language framework |
| XSL-FO | XSL Formatting Objects |
| XSL | Extensible Stylesheet Language |
| XSLT | Extensible Stylesheet Language Transformations |
* existed before XML
And there's more! Confused? I am!
As HTML has been superceded by XHTML, I haven't transferred my HTML notes to this site; links will point to the old site. I will concentrate on XHTML here. CSS is old technology which was used with HTML but it can still be used with XML, so it has been moved across.
Under construction