This page lists both the allowed and some proposed extension values for the rel attribute of the link, a and area elements in HTML. The best source for the most up-to-date information on rel values is the existing rel values page on the Microformats wiki. Also interesting is the rel registry page on the Microformats wiki and RelExtensions page on the WHATWG wiki.
| Keyword | link element |
a, area elements |
Brief description | Status/specification/source | Synonyms |
|---|---|---|---|---|---|
| acquaintance | Not allowed | External relation | The person represented by the current document considers the person represented by the referenced document to be an acquaintance. | XFN | |
| alternate | External resource | External relation | 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). |
HTML 4.01 link types | |
| appendix | Allowed | Allowed | Refers to a document serving as an appendix in a collection of documents. | HTML 4.01 link types | |
| bookmark | Not allowed | Allowed | 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. |
HTML 4.01 link types | |
| chapter | Allowed | Allowed | Refers to a document serving as a chapter in a collection of documents. | HTML 4.01 link types | |
| child | Not allowed | External relation | The referenced person is a child of the person represented by the current document. | XFN | |
| colleague | Not allowed | External relation | The referenced person is a colleague of the person represented by the current document. | XFN | |
| contact | Not allowed | External relation | The person represented by the current document considers the person represented by the referenced document to be a contact. | XFN | |
| contents | Allowed | Allowed | Refers to a document serving as a table of contents. Some user agents also support the synonym toc (from “Table of Contents”). |
HTML 4.01 link types | toc |
| copyright | Allowed | Allowed | Refers to a copyright statement for the current document. | HTML 4.01 link types | |
| co-resident | Not allowed | External relation | The referenced person lives in the same residence as the person represented by the current document. | XFN | |
| co-worker | Not allowed | External relation | The referenced person is a co-worker of the person represented by the current document. | XFN | |
| crush | Not allowed | External relation | This person considers the referenced person to be a crush (i.e. has a crush on the referenced person). | XFN | |
| date | Not allowed | External relation | This person considers the referenced person to be a date (i.e. is dating the referenced person). | XFN | |
| directory | Not allowed | External relation | …indicates that the destination of the hyperlink is a directory listing containing an entry for the current page. | Proposed | |
| enclosure | Not allowed | External relation | …indicates that the destination of that hyperlink is intended to be downloaded and cached. | Proposed | |
| friend | Not allowed | External relation | The person represented by the current document considers the person represented by the referenced document to be a friend. | XFN | |
| glossary | Allowed | Allowed | Refers to a document providing a glossary of terms that pertain to the current document. | HTML 4.01 link types | |
| help | Allowed | Allowed | Refers to a document offering help (more information, links to other sources information, etc.). | HTML 4.01 link types | |
| home | External relation | External relation | …indicates that the [referenced document] is the homepage of the site in which the current page appears. | Proposed | |
| kin | Not allowed | External relation | The referenced person is part of the extended family of the person represented by the current document. | XFN | |
| license | Allowed | Allowed | …indicates that the [referenced document] is a license for the current page. | rel-license | |
| me | External relation | External relation | The referenced document represents the same person as does the current document. | XFN | |
| met | Not allowed | External relation | This person has met the referenced person | XFN | |
| muse | Not allowed | External relation | The referenced person inspires the person represented by the current document. | XFN | |
| neighbor | Not allowed | External relation | The referenced person lives nearby the person represented by the current document. | XFN | |
| next | External relation | External relation | 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. | HTML 4.01 link types | |
| nofollow | Not allowed | External relation | Indicates that the destination of that hyperlink should not be afforded any additional weight or ranking by user agents which perform link analysis upon web pages (e.g. search engines). | rel-nofollow | |
| parent | Not allowed | External relation | The referenced person is a parent of the person represented by the current document. | XFN | |
| payment | Not allowed | External relation | …indicates that the destination of that hyperlink provides a way to show or give support for the current page. | Proposed | |
| prev | External relation | External relation | Refers to the previous document in an ordered series of documents. Some user agents also support the synonym “Previous.” | HTML 4.01 link types | previous |
| pronunciation | External relation | Not allowed | …indicates that the destination of the link element is a document providing a pronunciation lexicon for speech-synthesis purposes. | Proposed | |
| section | Allowed | Allowed | Refers to a document serving as a section in a collection of documents. | HTML 4.01 link types | |
| sibling | Not allowed | External relation | The referenced person is a sibling of the person represented by the current document. | XFN | |
| spouse | Not allowed | External relation | The referenced person is a spouse of the person represented by the current document. | XFN | |
| start | Allowed | Allowed | 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. | HTML 4.01 link types | |
| stylesheet | External resource | Not allowed | A style sheet for the current document used with the invisible <link href> element which is not ideal for content relationships. Content relationships should be user visible and thus uses with <a href> are strongly preferred. Unfortunately the use of stylesheet in user visible content like <a href> appears to be strictly theoretical. | HTML 4.01 link types | |
| subsection | Allowed | Allowed | Refers to a document serving as a subsection in a collection of documents. | HTML 4.01 link types | |
| sweetheart | Not allowed | External relation | This person considers the referenced person to be their sweetheart. | XFN | |
| tag | Not allowed | Allowed | …indicates that the [referenced document] is an author-designated “tag” (or keyword/subject) for the current page. | rel-tag | |
| transformation | Allowed | Allowed | Relates a source document to a transformation, usually represented in XSLT, that relates the source document syntax to the RDF graph syntax. Used in GRDDL. | GRDDL |