Resumen
Markup languages are static, do not process information, and can do nothing by themselves. However, programs can be written to take advantage of the knowledge encapsulated in the document structure so they can behave in a more intelligent manner. Hypertext Markup Language (HTML) is one of the simplest and most popular markup languages derived from SGML. An HTML file is a text file containing small markup tags that instruct the Web browser how to display the page. Extensible Markup Language (XML) is a restricted form of SGML. XML helps computers communicate better by separating presentation from content and by enabling information to be readily passed between applications. An important XML application in wireless and handheld devices is Wireless Markup Language (WML).