Hypertext Markup Language revision 5 (HTML5) is markup language for the structure and presentation of World Wide Web contents. HTML5 supports the traditional HTML and XHTML-style syntax and other new features in its markup, New APIs, XHTML and error handling.
HTML5 has been designed to deliver almost everything you'd want to do online without requiring additional software such as browser plugins. It does everything from animation to apps, music to movies, and can also be used to build incredibly complicated applications that run in your browser.
HTML5 is cross-platform, which means it doesn't care whether you're using a tablet or a smartphone, a netbook, notebook or ultrabook or a Smart TV: if your browser supports HTML5, it should work flawlessly.