HTML5------

by Beatrix

HTML5 is being developed as the next major revision of HTML (HyperText Markup Language), the core markup language of the World Wide Web. 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 February 2010^[update], the specification is in the "Last Call" state at the WHATWG.

HTML5 is the proposed next standard for HTML 4.01, XHTML 1.0 and DOM Level 2 HTML. It aims to reduce the need for proprietary plug-in-based rich internet application (RIA) technologies such as Adobe Flash, Microsoft Silverlight, Apache Pivot, and Sun JavaFX.

The ideas behind HTML5 were pioneered in 2004 by the WHATWG; HTML5 incorporates Web Forms 2.0, another WHATWG specification. The HTML5 specification was adopted as the starting point of the work of the new HTML working group of the W3C in 2007. This working group published the First Public Working Draft of the specification on January 22, 2008.^[3] 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.^[4]

The HTML5 editors are Ian Hickson of Google, Inc. and David Hyatt of Apple, Inc.

HTML5 introduces a number of new elements and attributes that reflect typical usage on modern Web sites. Some of them are semantic replacements for common uses of generic block (

) and inline () elements, for example

(website navigation block) and

. Other elements provide new functionality through a standardized interface, such as the and ^[ elements.

Some deprecated elements from HTML 4.01 have been dropped, including purely presentational elements such as and

, whose effects are achieved using Cascading Style Sheets. There is also a renewed emphasis on the importance of DOM scripting 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, , which enables standards-compliant rendering in all browsers that use "DOCTYPE sniffing".

Differences from HTML 4.01 and XHTML 1.x

The following is a cursory list of differences and some specific examples.

New parsing rules oriented towards flexible parsing and compatibility; not based on SGML
Ability to use inline SVG and MathML in text/html
New elements ? article, aside, audio, canvas, command, details, datalist, dialog, embed, figure, figcaption, footer, header, hgroup, keygen, mark, meter, nav, progress, output, rp, rt, ruby, section, source, summary, time, video
New types of form controls ? dates and times, email, url, search
New attributes ? ping (on a and area), charset (on meta), async (on script)
Global attributes (that can be applied for every element) ? id, tabindex, hidden, data-* (custom data attributes)
Forms will get support for PUT and DELETE methods too instead of just GET and POST (see Representational State Transfer for use cases)
Deprecated elements dropped ? center, font, frameset, strike

Error handling

An HTML5 (text/html) browser will be flexible in handling incorrect syntax. HTML5 is designed so that old browsers can safely ignore new HTML5 constructs. In contrast to HTML 4.01, the HTML5 specification gives detailed rules for lexing and parsing, with the intent that different compliant browsers will produce the same result in the case of incorrect syntax.