RelExtensions

This page is obsolete

The HTML specification no longer references this page. It now references the Microformats "existing-rel-values" registry: http://microformats.org/wiki/existing-rel-values

Historical contents

The following are the contents of this page before it was replaced.

This page lists the allowed extension values for the rel="" attribute in HTML5. You may add your own values to this list, which makes them legal HTML5 rel values. We ask that you try to avoid redundancy; if someone has already defined a value that does roughly what you want, please reuse it. Note that rel tokens are ASCII-lowercase before comparison against canonical value, so the canonical values should be listed without uppercase ASCII letters.

Keyword	Effect on link	Effect on a, area	Brief description	Link to more details	Synonyms	Status
pronunciation	external resource	not allowed	The referenced file contains a set of rules that associates strings of characters (e.g. words) with pronunciation instructions. For example, a rule can define whether the word "tomato" is to be spoken in the british or north-american way. These pronunciation rules should be processed by voice-enabled user-agents (e.g. web browsers that support TTS rendering), but conversely, "pronunciation" link/rel files can be completely ignored by systems that do not have speech capabilities. An example of possible format is W3C PLS (Pronunciation Lexicon Specification), with the MIME type "application/pls+xml" (and usually, the extension ".pls"). When several pronunciation lexicons are referenced within a single HTML document, and/or when a pronunciation rule is specified more than once for a given string of characters, the last occurrence of the rule takes precedence (in document order), such that any previously-defined pronunciation rule gets overridden.	Pronunciation Lexicon Specification (PLS) Version 1.0 (W3C Recommendation 14 October 2008) Previously-filed bug #7601		Proposal
accessibility	hyperlink	hyperlink	The linked document contains accessibility information for the linking document.	Bruce Lawson		Proposal
acquaintance	hyperlink	hyperlink	the person represented by the current document considers the person represented by the referenced document to be an acquaintance	XFN		Accepted
admin	hyperlink	hyperlink	The linked document contains administrative option(s) for the current document and related pages.		option	Proposal
ajax	not allowed	hyperlink	The link is controlled through javascript, and will load the page linked to though an ajax interface. Without javascript, it should behave as a normal "a" tag, and content change is done server side.			Proposal
alternate	See HTML5
answer	hyperlink	hyperlink	A link to the answer to the question this section or document asks, e.g. in a FAQ or in a sample exam. Unlike ‘reply’ or ‘comment’ this resource necessarily solves the problem.	Q&A	(reply, comment)	Proposal
application-manifest	external resource	Not allowed	A manifest for this web application. The manifest contains metadata about the web application, such as its name, description, and permissions the application might require.			Proposal
archives	See HTML5
author	See HTML5
bookmark	See HTML5
canonical	hyperlink	not allowed	Robots (e.g., search engines) should treat the document containing the tag as a minor variation of the linked document, which may result in the removal of the former from a web index and in the consolidation of its quality signals in the latter. Links with rel=canonical must not specify a language, type, or different kind of media; the referenced document must have the same language, type and target media.	[1]		Proposal
canonical-domain	external resource	not allowed	More than one domain may have largely similar or identical content but only one of the domains should be indexed for search engines. E.g., a company may have short and long domain names for the same content. For security against traffic theft, rev must be meaningless.	Google's analogous service and Talk for this page		Proposal
canonical-first	external resource	hyperlink	Where the canonical value should point to a group of pages, but the link can point to only one page, the group of pages can be clarified by choosing the first page in the group and assigning the URL for this rel link. For security against traffic theft, rev must be meaningless. This is only shorthand for providing two link elements, one on the noncanonical page to a "canonical" page and the other on the canonical page to the "first" page of the group. Where the group of pages corresponds to a subdirectory and a canonical URL value can point to the subdirectory resulting in a user arriving at the subdirectory's index page which is part of the group, this shorthand is unnecessary and one rel="canonical" will suffice.	Talk for this page		Proposal
canonical-human	external resource	hyperlink	Pages about a person across many websites can be associated based on name, nationality, birthplace, dates of birth and death, when flourished, and other identifiers. Search engines could more consistently aggregate same-person pages with less confusion due to name similarity.	W3C Bug 7681		Proposal
canonical-organization	external resource	hyperlink	Pages about an organization across many websites can be associated based on name, headquarters site, and other identifiers. Search engines could more consistently aggregate same-organization pages with less confusion due to name similarity.	W3C Bug 7682		Proposal
canonical-wwwnone	external resource	hyperlink	Both bare and www-prefixed domain names usually direct to the same site. Especially when external links to a site vary in the form used, search engine indexing concentrated on only one domain form may raise its credibility. The rel value is the form preferred for indexing, e.g., href="http://example.net". Nothing to the right of the top-level domain is needed. For security against traffic theft, rev must be meaningless.	Google's analogous service and Talk for this page		Proposal
chapter	hyperlink	hyperlink	Target document is a subdocument of the current document.	HTML4	section, subsection, appendix	Proposal
child	hyperlink	hyperlink	the referenced person is a child of the person represented by the current document	XFN		Accepted
co-resident	hyperlink	hyperlink	the referenced person lives in the same residence as the person represented by the current document	XFN		Accepted
co-worker	hyperlink	hyperlink	the referenced person is a co-worker of the person represented by the current document	XFN		Accepted
colleague	hyperlink	hyperlink	the referenced person is a colleague of the person represented by the current document	XFN		Accepted
contact	hyperlink	hyperlink	the person represented by the current document considers the person represented by the referenced document to be a contact	XFN		Accepted
contributor	hyperlink	hyperlink	The linked document is the page/email an agent (people or firm or...) involved in the production of the content, but not his main author(s).			Proposal
crush	hyperlink	hyperlink	this person considers the referenced person to be a crush (i.e. has a crush on the referenced person)	XFN		Accepted
date	hyperlink	hyperlink	this person considers the referenced person to be a date (i.e. is dating the referenced person)	XFN		Accepted
dns-prefetch	external resource	not allowed	Force the DNS lookup of specific hostnames.	Mozilla DNS Prefetching, Chromium DNS Prefetching		Proposal
edit	hyperlink	hyperlink	Target document is an editable version of the current document.	Atom Protocol		Proposal
edituri	hyperlink	not allowed	a link to an RSD file describing how to edit the given page.	rsd		Proposal
enclosure	hyperlink	hyperlink	the destination of the hyperlink is intended to be downloaded and cached.	rel-enclosure		Proposal
enlarged	not allowed	hyperlink	For anchors that have one child image element, indicates that the linked document is an image file which is the same as the child image element of the link except a larger size (dimensions).	David Goss		Proposal
external	See HTML5
extension	hyperlink	hyperlink	Browser extension	Mozilla Labs		Proposal
first	See HTML5
friend	hyperlink	hyperlink	the person represented by the current document considers the person represented by the referenced document to be a friend	XFN		Accepted
gallery	hyperlink	hyperlink	A graphic index that the current document or section is a part of or that illustrates the same topic.		(index, list)	Proposal
glossary	hyperlink	hyperlink	Target document provides definitions for words in current document.	HTML4		Proposal
help	See HTML5
hub	hyperlink	not allowed	Indicates a URL which implements both sides of the PubSubHubbub protocol.	PubSubHubbub		Proposal
i18nrules	hyperlink	not allowed	Target document provides ITS (Internationalization tag Set) rules for processing the current document.	ITS		Proposal
icon	See HTML5
index	See HTML5
jump	not allowed	hyperlink	Indicates a same page jump from the current fragment to another fragment. (E.g. sometimes online newspapers insert direct text saying "article continues below the image/advert" - they could instead use "jump" link. Ultimately, it indicates a page internal link.)	Talk		Proposal
kin	hyperlink	hyperlink	the referenced person is part of the extended family of the person represented by the current document	XFN		Accepted
lang-alt-[ISO 639-1 code]	hyperlink	hyperlink	The linked document contains a version of the current document in an alternative language. "[ISO 639-1 code]" is replaced with the appropriate ISO 639-1 language code. The ISO 639-1 code is used when the browser (or other user agent) wants to display either the full name of the language or a flag, as a visual aid for the end user.			Proposal
lang-orig-[ISO 639-1 code]	hyperlink	hyperlink	The linked document contains a version of the current document in the language the document was originally written in. "[ISO 639-1 code]" is replaced with the appropriate ISO 639-1 language code. The ISO 639-1 code is used when the browser (or other user agent) wants to display either the full name of the language or a flag, as a visual aid for the end user.			Proposal
last	See HTML5
latest-version	hyperlink	hyperlink	The referenced document is the latest version of the current document.	[2], RFC5829		Proposal
license	See HTML5
login	hyperlink	hyperlink	The login keyword indicates that the referenced document provides an interface (user, pwd) to authenticate a registered user of the page/or to registrate a new user.		search	Proposal
logout	external resource	not allowed	The linked document provides a resource for the UA to request when all currently open documents of the same "group" are closed (to facilitate logging out the current user).	LogoutRelExtension		Proposal
longdesc	hyperlink	hyperlink	Related to ISSUE-30. AT should treat an element wrapped in a link with rel="longdesc" as equivalent to an element with longdesc="URI".	(1) Eric Eggert's original proposal, 25th of June 2007, (2) Maciej's comment, 25th of June 2007, (3) Bug 10434, the HTMLwg, 2010 (4) rel="longdesc" listed as POSH in Microformats.org	<foo longdesc="URL"/> is synonymous to <a rel="longdesc" href="URL"><foo/></a>	Proposal
map	hyperlink	hyperlink	the referenced document represents a map of the location of the subject of the current document; parsers may use the URI or target page to determine coordinates.	to follow		Proposal
me	hyperlink	hyperlink	the referenced document represents the same person as does the current document	XFN		Accepted
met	hyperlink	hyperlink	this person has met the referenced person	XFN		Accepted
meta	external resource	hyperlink	publishing RDF/FOAF files	RDF, FOAF		Proposal
muse	hyperlink	hyperlink	the referenced person inspires the person represented by the current document	XFN		Accepted
neighbor	hyperlink	hyperlink	the referenced person lives nearby the person represented by the current document	XFN		Accepted
next	See HTML5
next-archive	hyperlink	hyperlink	A URI that refers to the immediately following archive document.	Atom Link Relations, RFC5005		Proposal
nofollow	See HTML5
noreferrer	See HTML5
noprefetch	external resource	hyperlink	Denies prefetching (not fetching) as a cost-control option for website owners, especially where pages are dynamic, leading to prefetching of wrong and useless pages. The link provides a per-page denial whereas a and area provide a per-element denial. For link, attributes rel="noprefetch" denies prefetching of the page at the href URL and rev="noprefetch" denies prefetching of the page bearing the link. For a and area, rel is as above and rev is meaningless.	W3C Bug 7918		Proposal
note	not allowed	hyperlink	An in-page or out-page jump to a footnote. This encompasses note, footnote, endnote, and sidenote.	Talk		Proposal
openid.delegate	external resource	not allowed	OpenID 1.1 authentication delegation	OpenID specification		Proposal
openid.server	external resource	not allowed	OpenID 1.1 authentication delegation	OpenID specification		Proposal
openid2.local_id	external resource	not allowed	OpenID 2.0 authentication delegation	OpenID Auth 2.0 section 7.3.3		Proposal
openid2.provider	external resource	not allowed	OpenID 2.0 authentication endpoint	OpenID Auth 2.0 section 7.3.3		Proposal
parent	hyperlink	hyperlink	the referenced person is a parent of the person represented by the current document	XFN		Accepted
payment	hyperlink	hyperlink	A URI where payment is accepted.	Atom Link Relations		Proposal
pgpkey	hyperlink	not allowed	The linked document is the PGP public key file (which may contain multiple keys) of the author(s) of the page.	[3], [4]		Proposal
pingback	See HTML5
prefetch	See HTML5
presentation	external resource	hyperlink	Like ‘print’ this relation references a resource that represents the same content or topic, but in a very different manner. It is similar to media=projection, but is to be used where text is substituted by graphics, animations and sounds, which goes beyond mere style switching. This relation is also appropriate for links from thumbnail to full resolution images.		slides, slideshow	Proposal
prev	See HTML5
prev-archive	hyperlink	hyperlink	A URI that refers to the immediately preceding archive document.	Atom Link Relations, RFC5005		Proposal
print	external resource	hyperlink	The referenced document is recommended for printing, even though the referent document is capable of being printed and both documents are of the same type, medium, and language. A typical case is where content spread over multiple pages is also available on a single page that is more convenient to print. This is semantically more specific than "canonical" and "alternate". Where type, medium, and/or language differ, consider "alternate"; where any of them differ but the purpose is printing, consider applying both values.	W3C Bug 7645		Proposal
profile	hyperlink	hyperlink	this referenced link is a metadata profile for the current document	HTML Meta data profiles, Example of profile in a-elements		Proposal
question	hyperlink	hyperlink	A link to the question this section or document answers, e.g. in a FAQ or in a sample exam.	Q&A	topic, subject, problem, (up)	Proposal
related	hyperlink	hyperlink	this referenced link identifies a resource related to the current document	Atom Syndication Format		Proposal
reply	hyperlink	hyperlink	A follow-up posting to this document or section or in the thread this document or section is an index of.	Thread	posting, comment	Proposal
resource-package	external resource	not allowed	The linked document is a zipped resource package	Resource Packages		Proposal
resources	external resource	not allowed	a higher level alternative to HTTP Content Negotiation for other resources linked from the document, in a yet to be specified format		resource-description, content-negotiation	Proposal
reviewer	hyperlink	not allowed	The linked document is the page/email an agent (people or firm or...) responsible for reviewing the content.	[5]		Proposal
script	not allowed	not allowed	Was proposed to replace <script>. Use <script> instead.	none		Rejected
search	See HTML5
self	hyperlink	hyperlink	A URI that refers to a resource equivalent to the containing element.	Atom Link Relations, RFC4287		Proposal
service	external resource	not allowed	Points to a resource describing a service API	ServiceRelExtension		Proposal
shortlink	hyperlink	hyperlink	Identifies a shorter form of the URL for the current document, provided by the document owner.	shortlink Specification		Proposal
sibling	hyperlink	hyperlink	the referenced person is a sibling of the person represented by the current document	XFN		Accepted
sidebar	See HTML5
spouse	hyperlink	hyperlink	the referenced person is a spouse of the person represented by the current document	XFN		Accepted
statechart	external resource	not allowed	A reference to an SCXML document that controls the application-flow of the current HTML document	SCXML		Proposal
stylesheet	See HTML5
subresource	hyperlink	not allowed	The referenced document is a subresource of the current document.			Proposal
sweetheart	hyperlink	hyperlink	this person considers the referenced person to be their sweetheart	XFN		Accepted
tag	See HTML5
technicalauthor	hyperlink	hyperlink	The linked document is the page/email an agent (people or firm or...) responsible for the technical construction of the page (i.e. the HTML/CSS/PHP code), not for the content.			Proposal
thread	hyperlink	hyperlink	A hierarchic list of topic(s) and replies where this document or section belongs to either one.	Thread	(index)	Proposal
timesheet	external resource	not allowed	SMIL Timesheet	SMIL Timesheets 1.0		Proposal
topic	hyperlink	hyperlink	The initial posting this document or section is a reply to or index of.	Thread	subject, (top)	Proposal
translatedfrom	hyperlink	hyperlink	The linked document is the page/email that has been translation source for the current document. It also indicates that the current document is a translation and not an original work.			Proposal
translator	hyperlink	hyperlink	The linked document is the page/email an agent (people or firm or...) responsible for the translation of the page. It also indicates that the current page is a translation of an other document, which should be linked through a rel="translatedfrom".			Proposal
up	See HTML5
us	hyperlink	hyperlink	The referenced document represents the same organisation as does the current document [cf rel-me]			Proposal
webmaster	hyperlink	hyperlink	The linked document is the page/email an agent (people or firm or...) available for requests about the content of the page.		maintainer	Proposal
widget	hyperlink	hyperlink	Points to a widget.	Widgets 1.0 Editor's draft		Proposal
wlwmanifest	hyperlink	not allowed	A link to a manifest for Windows Live Writer.	msdn		Proposal

The "Effect on link" column must either say "not allowed" if the rel value is not allowed on <link> elements, "hyperlink" if the rel value creates a hyperlink, or "external resource" if the rel value creates a link to an external resource.

The "Effect on a and area" column must either say "not allowed" or "hyperlink".

For the "Status" section to be changed to "Accepted", the proposed keyword must either have been through the Microformats process, and been approved by the Microformats community; or must be defined by a W3C specification in the Candidate Recommendation or Recommendation state. If it fails to go through this process, it is "Rejected".

For more details, see the HTML5 specification.

See also

• the Microformats wiki page on this matter.
• How to use Citation Typing Ontology (CiTO) in your blog posts - proposes several values for marking up academic citations, but confuses the direction of the relationship (note comments)