Abstraction Levels in Web Document Formats

摘要

The paper gives an overview of current and emerging document formats on the Web, and discusses the abstraction level of the different formats. The "ladder of abstraction" is introduced as a measuring stick for Web formats, and various levels from presentation (at the bottom of the ladder) to semantics (at the top) is described. The importance of reaching certain abstraction levels in order to support device-independent formats, universal accessibility, and scalable presentations is stressed. The document formats discussed in the paper are: HTML, PDF, GIF, PNG, MathML, and XSL-FO. Also, the effect of style and transformation languages (namely CSS and XSLT) are described.