HTML:
HTML is a markup language used to create static Webpages.
HTML provides a way to describe the structure of graphics and text on a web page. In HTML, audio and video requires external software support.
HTML standard were and are created by World Wide Web consortium (W3C). HTML is derived from a more general markup language called Standard Generalized Markup Language (SGML), which is an International Organization for Standardization (ISO) technology that defines markup languages.
In HTML, finding correct GeoLocation is impossible.

HTML5:
HTML5 is markup language for structuring and presenting content for the World Wide Web, and is a core technology of the Internet originally proposed by Opera Software. HTML5 is the latest revision of HTML containing much better support for media like video and audio tags. It also defines detailed parsing rules (including "error handling") for this syntax which is largely compatible with popular implementations.  HTML5 is cooperation between the World Wide Web Consortium (W3C) and the Web Hypertext Application Technology Working Group (WHATWG).WHATWG was working with web applications and forms and W3C was working with XHTML 2.0. In 2006, they decided to cooperate and create a new version of HTML.