Like its immediate predecessors, HTML 4.01 and XHTML 1.1, HTML5 is a standard for structuring and presenting content on the World Wide Web. It incorporates new features for the control of embedded audio and video, and the utilization of drag-and-drop—historically implemented in various ways depending on platform.
W3C standardization process
The Web Hypertext Application Technology Working Group (WHATWG) started work on the specification in June 2004 under the name Web Applications 1.0. As of March 2010, the specification is in the Draft Standard state at the WHATWG, and in Working Draft state at the W3C. Ian Hickson of Google, Inc. is the editor of HTML5.
The HTML5 specification was adopted as the starting point of the work of the new HTML working group of the World Wide Web Consortium (W3C) in 2007. This working group published the First Public Working Draft of the specification on January 22, 2008. The specification is an ongoing work, and is expected to remain so for many years, although parts of HTML5 are going to be finished and implemented in browsers before the whole specification reaches final Recommendation status.
According to the W3C timetable, it is estimated that HTML5 will reach W3C Recommendation by late 2010. However, the First Public Working Draft estimate was missed by 8 months, and Last Call and Candidate Recommendation were expected to be reached in 2008, but as of July 2010 HTML5 is still at Working Draft stage in the W3C. HTML5 has been at Last Call in the WHATWG since October 2009.
Ian Hickson, editor of the HTML5 specification, expects the specification to reach the Candidate Recommendation stage during 2012. The criterion for the specification becoming a W3C Recommendation is “two 100% complete and fully interoperable implementations”. In an interview with TechRepublic, Hickson guessed that this would occur in the year 2022 or later. However, many parts of the specification are stable and may be implemented in products:
Some sections are already relatively stable and there are implementations that are already quite close to completion, and those features can be used today.
– WHAT Working Group, When will HTML5 be finished?
Markup
HTML5 introduces a number of new elements and attributes that reflect typical usage on modern websites. Some of them are semantic replacements for common uses of generic block (div) and inline (span) elements, for example nav (website navigation block), footer (usually referring to bottom of web page or to last lines of HTML code), or audio and video instead of object. Some deprecated elements from HTML 4.01 have been dropped, including purely presentational elements such as font and center, whose effects are achieved using Cascading Style Sheets. There is also a renewed emphasis on the importance of DOM scripting (e.g., JavaScript) in Web behavior.
The HTML5 syntax is no longer based on SGML despite the similarity of its markup. It has, however, been designed to be backward compatible with common parsing of older versions of HTML. It comes with a new introductory line that looks like an SGML document type declaration, doctype html, which triggers the standards-compliant rendering mode. HTML5 also incorporates Web Forms 2.0, another WHATWG specification.
New APIs
In addition to specifying markup, HTML5 specifies scripting application programming interfaces (APIs). Existing document object model (DOM) interfaces are extended and de facto features documented. There are also new APIs, such as:
- The canvas element for immediate mode 2D drawing. See Canvas 2D API Specification 1.0 specification
- Timed media playback
- Offline storage database (offline web applications). See Web Storage
- Document editing
- Drag-and-drop
- Cross-document messaging
- Browser history management
- MIME type and protocol handler registration.
- Microdata
- Geolocation
- Web SQL Database, a local SQL Database.
- The Indexed Database API, an indexed hierarchical key-value store (formerly WebSimpleDB).
