HTML5

HTML5 is the fifth major version of the HTML markup language and, more broadly, the umbrella name for the set of APIs and elements that turned the browser into an application runtime. It originated outside the W3C, as the WHATWG's Web Applications 1.0 and Web Forms 2.0 drafts, which were merged and renamed in 2007. In May of that year the W3C's new HTML working group adopted the WHATWG draft as its starting point. The first W3C public working draft, edited by Ian Hickson of Google and David Hyatt of Apple, was published on 22 January 2008. HTML5 became a full W3C Recommendation on 28 October 2014. The design principles departed sharply from the contemporaneous XHTML 2.0 effort. HTML5 preserves backwards compatibility with existing content, including tag soup authored over the previous fifteen years. It specifies a parsing algorithm in such detail that conformant implementations must produce identical DOMs even for malformed input, replacing the older world in which every browser invented its own error recovery. It treats the language as text/html with optional XML serialization (XHTML5), avoiding XML's draconian error handling. The feature surface that shipped under the HTML5 banner is large: the ``<video>`` and ``<audio>`` elements, ``<canvas>`` 2D drawing, semantic structural elements like ``<article>`` and ``<section>``, new form input types, offline application caches, local storage, Web Workers, WebSockets, and a richer set of accessibility hooks via ARIA integration. After 2014 the W3C and WHATWG continued publishing competing snapshots and Living Standards respectively, with growing philosophical divergence about whether HTML should be a frozen versioned standard or a continuously updated one. In May 2019 the two bodies signed a memorandum naming WHATWG the sole publisher of HTML and DOM. The W3C formally retired its HTML5 Recommendation in 2018, redirecting readers to the Living Standard.