HTML 5.1

W3C Proposed Recommendation,

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This specification defines the 5th major version, first minor revision of the core language of the World Wide Web: the Hypertext Markup Language (HTML). In this version, new features continue to be introduced to help Web application authors, new elements continue to be introduced based on research into prevailing authoring practices, and special attention continues to be given to defining clear conformance criteria for user agents in an effort to improve interoperability.

Status of this document

This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at https://www.w3.org/TR/.

This is a Proposed Recommendation for HTML 5.1 that would obsolete the HTML 5.0 Recommendation. An HTML 5.1 Candidate Recommendation was published on 21 June 2016, and this document has incorporated feedback received on that draft.

W3C Advisory Committee members are invited to advise the Director on whether this document should become a W3C Recommendation through the relevant questionnaire in their WBS questionnaires, before 13 October 2016.

Errata for this document are recorded as issues. The latest HTML editors' draft shows the current proposed resolution of errata in situ.

All interested parties are invited to provide implementation and bug reports and other comments through the Working Group's Issue tracker. These will generally be considered in the development of HTML 5.2.

The implementation report produced for this version demonstrates that in almost every case changes are matched by interoperable implementation. In the instances where there is not yet interoperable implementation, there are warnings explicitly pointing this out:

Matching for the :dir CSS pseudo-class selectors
This is implemented in Firefox. It cannot be tested directly without a matching implementation of the CSS selector itself. It is not an HTML feature per se, it is a description that matches the CSS selector to HTML's directionality algorithm.
Unhandled promise rejection and {{rejectionhandled}}
This feature has been partially implemented in Blink. Promises are becoming an integral part of the Web Platform, and this was adopted for consistency with WHATWG.
Making createTFoot() insert at the end of a table
This is currently implemented in Firefox. There is poor interoperabiity in this area, but this is a desirable behaviour, and provides consistency with WHATWG.
probablySupportsContext() for <{canvas}>
This is a convenience function meant to return false if called on a canvas that definitely doesn't support the relevant context, and true otherwise. It is not currently known to be implemented in any browser.
The close() method for blobs, and hooks added for CSP 3 blocking styles and events
The places where these are mentioned are in algorithms. If they are not implemented, there is no problem caused as the algorithm continues to work as expected.

Of the items marked "at risk" in the Candidate Recommendation, the following have been removed:

The remaining items were retained:

The Working Group aims to recharter at the end of October, and to produce an HTML 5.2 Recommendation in late 2017 that would obsolete the HTML 5.1 Recommendation it aims to publish in late 2016 based on this draft.

This document was published by the Web Platform Working Group as a Proposed Recommendation. This document is intended to become a W3C Recommendation. Feedback and comments on this specification are welcome. Please use Github issues. Historical discussions can be found in the public-html@w3.org archives.

Publication as a Proposed Recommendation does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.

This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.

This document is governed by the 1 September 2015 W3C Process Document.