What is HTML5?
HTML5 will be the new standard for HTML, XHTML, and the HTML DOM.
The previous version of HTML came in 1999. The web has changed a lot since then.
HTML5 is still a work in progress. However, most modern browsers have some HTML5 support.

How Did HTML5 Get Started?
HTML5 is a cooperation between the World Wide Web Consortium (W3C) and the Web Hypertext Application Technology Working Group (WHATWG).
WHATWG was working with web forms and applications, and W3C was working with XHTML 2.0. In 2006, they decided to cooperate and create a new version of HTML.

Some rules for HTML5 were established:
    New features should be based on HTML, CSS, DOM, and JavaScript
    Reduce the need for external plugins (like Flash)
    Better error handling
    More markup to replace scripting
    HTML5 should be device independent
    The development process should be visible to the public

New Features :-
Some of the most interesting new features in HTML5:
    The canvas element for drawing
    The video and audio elements for media playback
    Better support for local offline storage
    New content specific elements, like article, footer, header, nav, section
    New form controls, like calendar, date, time, email, url, search