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 prerender external resource not allowed Prerender the specified URL including all subresources and running all scripts. Chromium Prerendering Proposal 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