HTML5 is a markup language for structuring and presenting content for the World Wide Web, and is a core technology of the Internet originally proposed by Opera Software.[2] It is the fifth revision of the HTML standard (created in 1990 and standardized as HTML4 as of 1997)[3] and, as of October 2012, is still under development. Its core aims have been to improve the language with support for the latest multimedia while keeping it easily readable by humans and consistently understood by computers and devices (web browsers, parsers, etc.). HTML5 is intended to subsume not only HTML 4, but XHTML 1 and DOM Level 2 HTML as well.[3]

 

HTML5 is not software that has to be installed but rather a new version of the language HTML. Web browsers must support this new version of HTML in order to correctly display web pages using HTML5 functions. It is upon the developers of browsers to update their software to use HTML5; users simply must allow these updates to be done on their computers, but do not have to install additional software.

 

Following its immediate predecessors HTML 4.01 and XHTML 1.1, HTML5 is a response to the observation that the HTML and XHTML in common use on the World Wide Web are a mixture of features introduced by various specifications, along with those introduced by software products such as web browsers, those established by common practice, and the many syntax errors in existing web documents.[4] It is also an attempt to define a single markup language that can be written in either HTML or XHTML syntax. It includes detailed processing models to encourage more interoperable implementations; it extends, improves and rationalises the markup available for documents, and introduces markup and application programming interfaces (APIs) for complex web applications.[5] For the same reasons, HTML5 is also a potential candidate for cross-platform mobile applications. Many features of HTML5 have been built with the consideration of being able to run on low-powered devices such as smartphones and tablets. In December 2011 research firm Strategy Analytics forecast sales of HTML5 compatible phones will top 1 billion in 2013.[6]

 

In particular, HTML5 adds many new syntactic features. These include the new