Source: https://en.wikipedia.org/wiki/HTML5

• HTML5 is a markup language used for structuring and presenting content on the WWW.
• Published in October 2014 by the World Wide Web Consortium (W3C)
• to improve the language with support for the latest multimedia,
• keep the language easily readable by humans—and consistently understood by computers and devices such as web browsers, parsers, etc.
• HTML5 includes detailed processing models to encourage more interoperable implementations;
• it extends, improves and rationalizes the markup available for documents,
• and introduces markup and application programming interfaces (APIs) for complex web applications.
• For the same reasons, HTML5 is also a candidate for cross-platform mobile applications, because it includes features designed with low-powered devices such as smartphones and tablets in mind.
• Many new improvements:
• Syntatic: – natively include and handle multimedia and graphical content, the new <video>, <audio> and <canvas> elements were added, and support for scalable vector graphics (SVG) content and MathML for mathematical formulas.
• Page structure elements: – such as <main>, <section>, <article>, <header>, <footer>, <aside>, <nav> and <figure>, are added.
• New attributes are introduced, some elements and attributes have been removed, and others such as <a>, <cite> and <menu> have been changed, redefined or standardized.
• The APIs and Document Object Model (DOM) are now fundamental parts of the HTML5 specification and HTML5 also better defines the processing for any invalid documents.