Hypertext Markup Language (HTML) is the familiar language used to display Web pages. A subset of HTML, Wireless Markup Language (WML) is specifically designed to present Web-based information on small handheld devices like mobile phones.
Extensible Markup Language (XML) is a language for documents that contain structured information. You can define custom tags and the structural relationships between them based on the content of your document. Because an XML document contains information about itself, it is an excellent vehicle for transporting data from one location to another, for example, between applications or between organizations.