existing-rel-values
existing rel values
usage
rel values indicate the relationship of the target resource to the resource on which they appear. In microformats, rel are used on links (e.g. <a rel="home" href="http://example.org">). Elsewhere, they are also used on link headers (e.g. <link rel="start" href="http://example.org/section/page1.htm">.
Multiple values may be used, in the same manner as multiple class values (e.g. <a rel="home me contents" href="http://example.org">).
rev
In (X)HTML, the same values may be used as rev ("reverse relationship") values, to indicate the relationship of the resource on which they appear to the target resource. Such use (apart from the "grand-fathered" case of VoteLinks) is deprecated in microformats.
formats
These rel values are defined formats from specifications (HTML 4, microformats) are thus are recommended for general use. Alphabetically ordered by value.
Note: this list is incomplete, please help complete it from the following sources:
- HTML 4 link type
- xfn and other microformats
| rel value | summary (from the relevant specification where possible)) |
defining specification |
|---|---|---|
| alternate | Designates substitute versions for the document in which the link occurs. When used together with the lang attribute, it implies a translated version of the document. When used together with the media attribute, it implies a version designed for a different medium (or media). |
HTML4 link type |
| appendix | Refers to a document serving as an appendix in a collection of documents. | HTML4 link type |
| author | ... | ??? |
| bookmark | Refers to a bookmark. A bookmark is a link to a key entry point within an extended document. The title attribute may be used, for example, to label the bookmark. Note that several bookmarks may be defined in each document. |
HTML4 link type |
| chapter | Refers to a document serving as a chapter in a collection of documents. | HTML4 link type |
| contents | Refers to a document serving as a table of contents. Some user agents also support the synonym ToC (from "Table of Contents"). | HTML4 link type |
| copyright | Refers to a copyright statement for the current document. | HTML4 link type |
| friend | the person represented by the current document considers the person represented by the referenced document to be a friend | XFN |
| glossary | Refers to a document providing a glossary of terms that pertain to the current document. | HTML4 link type |
| help | Refers to a document offering help (more information, links to other sources information, etc.) | HTML4 link type |
| index | Refers to a document providing an index for the current document. | HTML4 link type |
| me | the referenced document represents the same person as does the current document | XFN |
| home | …indicates that the [referenced document] is the homepage of the site in which the current page appears. | rel-home |
| license | …indicates that the [referenced document] is a license for the current page. | rel-license |
| microsummary | … | Microsummary |
| next | Refers to the next document in a linear sequence of documents. User agents may choose to preload the "next" document, to reduce the perceived load time. | HTML4 link type |
| prev | Refers to the previous document in an ordered series of documents. Some user agents also support the synonym "Previous". | HTML4 link type |
| previous | Synonym of prev |
HTML4 link type |
| schema.DC | … | Dublin Core |
| schema.DCTERMS | … | Dublin Core |
| search | … | ??? |
| section | Refers to a document serving as a section in a collection of documents. | HTML4 link type |
| start | Refers to the first document in a collection of documents. This link type tells search engines which document is considered by the author to be the starting point of the collection. | HTML4 link type |
| stylesheet | a style sheet for the current document | HTML4 link type |
| subsection | Refers to a document serving as a subsection in a collection of documents. | HTML4 link type |
| tag | …indicates that the [referenced document] is an author-designated "tag" (or keyword/subject) for the current page. | rel-tag |
| toc | Synonym of contents (from "Table Of Contents") |
HTML4 link type |
notes
rel="alternate"can take further meaning from additional attributes, such asrel="alternate" lang="fr"(French language version of this page);rel="alternate" media="print"(printable version of this page) etc.
- Synonyms such as "previous", "toc" are not as widely supported as the main term.
brainstorming
Several rel values are being brainstormed as potential microformats and are thus listed here. If you find you have a use for such semantics in real world examples, consider trying out these values and provide feedback on the respective brainstorming page(s) with your results/experience.
Sources: group-brainstorming, ...
| rel value | summary | proposed in |
|---|---|---|
| group | the referenced document represents a group that the person represented by the current document belongs to | group-brainstorming |
| member | the referenced document represents a member of the group represented by the current document | group-brainstorming |
external proposals
- Web Communication Link Relationships. Includes:
- user
- contribution
- referral
- pingback
- trackback
- permalink
- comment
- archive
- feed
- sponsor
- endorsed
- unendorsed
dropped
The following rel values were in earlier version(s) of specification(s) and it is presumed by their absence from the most recent version of the respective specification(s) that they have been deprecated or obsoleted. Use of them could be considered a bit more standard than just POSH, although you may wish to research why such values were omitted from latter specifications before using them. If you do discover the reasoning, please add a short statement or link to thereof into the appropriate place in the following table.
Sources: HTML3 (expired!) - (has been superceded by HTML 3.2 - which itself has been superceded by HTML 4.0 - which itself has been updated by HTML 4.01, commonly referred to as "HTML 4" in this wiki and other places.)
| rel value | summary | defining specification | why dropped |
|---|---|---|---|
| banner | Was used to reference another document to be used as banner for this document (i.e. a form of "include" statement). | HTML 3 | unknown |
| up | When the document forms part of a hierarchy, this link references the immediate parent of the current document. | HTML 3 | unknown |
POSH usage
There are numerous rel values used as POSH in the wild, their origins are not necessarily known, nor are their meanings consistent, but it may still be useful to document their existence and summarize their implied meanings/usage intent.
| rel value | summary | origin |
|---|---|---|
| archive | index of archived entries | Web Communication Link Relationships (see above) |
tools
See implementations.