HTML stands for Hyper Text Markup Language. HTML is the standard markup language for creating Web pages. HTML describes the structure of a Web page.

XHTML stands for Extensible Hypertext Markup Language. XHTML is a stricter, more XML-based version of HTML. XHTML is HTML defined as an XML application. XHTML is supported by all major browsers.

Microdata is data on the characteristics of units of a population, such as individuals, households, or establishments, collected by a census, survey, or experiment.

The Hypertext Transfer Protocol is an application layer protocol for distributed, collaborative, hypermedia information systems..