<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 Web Hypertext Application Technology Working Group (WHATWG) began work on the new standard in 2004. At that time, HTML 4.01 had not been updated since 2000, and the World Wide Web Consortium (W3C) was focusing future developments on XHTML 2.0. In 2009, the W3C allowed the XHTML 2.0 Working Group’s charter to expire and decided not to renew it.
The Mozilla Foundation and Opera Software presented a position paper at a World Wide Web Consortium (W3C) workshop in June 2004, focusing on developing technologies that are backward-compatible with existing browsers, including an initial draft specification of Web Forms 2.0. The workshop concluded with a vote—8 for, 14 against—for continuing work on HTML. Immediately after the workshop, WHATWG was formed to start work based upon that position paper, and a second draft, Web Applications 1.0, was also announced. The two specifications were later merged to form HTML 5. The HTML 5 specification was adopted as the starting point of the work of the new HTML working group of the W3C in 2007.
On 14 February 2011, the W3C extended the charter of its HTML Working Group with clear milestones for HTML 5. In May 2011, the working group advanced HTML 5 to “Last Call”, an invitation to communities inside and outside W3C to confirm the technical soundness of the specification. The W3C developed a comprehensive test suite to achieve broad interoperability for the full specification by 2014, which was the target date for recommendation. In January 2011, the WHATWG renamed its “HTML5” specification HTML Living Standard. The W3C nevertheless continued its project to release HTML 5.
In July 2012, WHATWG and W3C decided on a degree of separation. W3C will continue the HTML 5 specification work, focusing on a single definitive standard, which is considered as a “snapshot” by WHATWG. The WHATWG organization continues its work with HTML 5 as a “living standard”. The concept of a living standard is that it is never complete and is always being updated and improved. New features can be added but functionality will not be removed.
On 16 September 2014, W3C moved HTML 5 to Proposed Recommendation. On 28 October 2014, HTML 5 was released as a W3C Recommendation, bringing the specification process to completion. On 1 November 2016, HTML 5.1 was released as a W3C Recommendation. On 14 December 2017, HTML 5.2 was released as a W3C Recommendation.
The combined timelines for HTML 5.0, HTML 5.1 and HTML 5.2:
|Version||First draft||Candidate recommendation||Recommendation|
W3C and WHATWG have been characterized as both working together on the development of HTML 5, and yet also at cross purposes ever since the July 2012 split of the W3C work into milestone-based static standards and WHATWG’s into a continually updated “living standard”. The relationship has been described as “fragile”, even a “rift”, and characterized by “squabbling”.
In at least one case, namely the permissible content of the
<cite> element, the two specifications directly contradict each other (as of July 2018), with the W3C definition being permissive and reflecting traditional use of the element since its introduction, but WHATWG limiting it to a single defined type of content (the title of the work cited). This is actually at odds with WHATWG’s stated goals of ensuring backward compatibility and not losing prior functionality.
The “Introduction” section in the WHATWG spec (edited by Ian “Hixie” Hickson) is critical of W3C, e.g. “Note: Although we have asked them to stop doing so, the W3C also republishes some parts of this specification as separate documents.” In its “History” subsection it portrays W3C as resistant to Hickson’s and WHATWG’s original HTML 5 plans, then jumping on the bandwagon belatedly (though Hickson was in control of the W3C HTML 5 spec, too). Regardless, it indicates a major philosophical divide between the organizations:
For a number of years, both groups then worked together. In 2011, however, the groups came to the conclusion that they had different goals: the W3C wanted to publish a “finished” version of “HTML5”, while the WHATWG wanted to continue working on a Living Standard for HTML, continuously maintaining the specification rather than freezing it in a state with known problems, and adding new features as needed to evolve the platform.
Since then, the WHATWG has been working on this specification (amongst others), and the W3C has been copying fixes made by the WHATWG into their fork of the document (which also has other changes).
The “markets” for the two specifications are largely different. The W3C spec is the one that Web developers most often refer to, while the WHATWG version is used by the software development teams of the browser makers (though a version exists for Web content authors, trimmed of the material only of interest to browser coders). New features are added to HTML and, often experimentally, to browsers long before they appear in a W3C spec, because they arise in the WHATWG one. The technology journal Ars Technica observed that “both groups are likely to continue to exist, and both groups will continue to have broad-based industry backing”.