HTML 5 (formerly spelled HTML5) is a markup language used for structuring and presenting content on the World Wide Web. It is the fifth and current major version of the HTML standard, and subsumes XHTML. It currently exists in two standardized forms. HTML 5.2 Recommendation by the World Wide Web Consortium (W3C, a broad coalition of organizations), intended primarily for Web content developers; and HTML Living Standard by WHATWG (a small consortium of four browser vendors), intended primarily for browser developers, though it also exists in an abridged Web developer version. There are minor conflicts between the two groups' specifications.
HTML 5 was first released in public-facing form on 22 January 2008, with a major update and "W3C Recommendation" status in October 2014. Its goals are to improve the language with support for the latest multimedia and other new features; to keep the language both easily readable by humans and consistently understood by computers and devices such as Web browsers, parsers, etc., without XHTML's rigidity; and also to remain backward-compatible with older software. HTML 5 is intended to subsume not only HTML 4, but also XHTML 1 and DOM Level 2 HTML; the HTML 4 and XHTML specs were announced as superseded by HTML 5.2 on 27 March 2018.
HTML 5 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, HTML 5 is also a candidate for cross-platform mobile applications, because it includes features designed with low-powered devices in mind.
Many new syntactic features are included. To natively include and handle multimedia and graphical content, the new
<canvas> elements were added, and support for scalable vector graphics (SVG) content and MathML for mathematical formulas. To enrich the semantic content of documents, new page structure elements such as
<figure>, are added. New attributes are introduced, some elements and attributes have been removed, and others such as
<menu> have been changed, redefined, or standardized.
The APIs and Document Object Model (DOM) are now fundamental parts of the HTML 5 specification and HTML 5 also better defines the processing for any invalid documents.