REL=Home The link references a home page or the top of some hierarchy.
HOME
RESERVED. Defined by the user (for example, using an
environment variable or preference, e.g. WWW_HOME).
This relationship may not be overridden; HTML user agents
should ignore any author-supplied REL=HOME setting.
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.
BEGIN or FIRST The BEGIN relationship identifies the author- defined start of a sequence of documents of which the current document is a node. TOP is a functional equivalent to BEGIN when only one of these values is specified. When REL=BEGIN, the target document is the beginning of the sequence. When REV=BEGIN, the current document is the beginning of the sequence. If the hypertext link is specified with REL in a LINK element, an HTML user agent may present an icon in a tool bar.
BEGIN or FIRST The BEGIN relationship identifies the author- defined start of a sequence of documents of which the current document is a node. TOP is a functional equivalent to BEGIN when only one of these values is specified. When REL=BEGIN, the target document is the beginning of the sequence. When REV=BEGIN, the current document is the beginning of the sequence. If the hypertext link is specified with REL in a LINK element, an HTML user agent may present an icon in a tool bar.
END or LAST The END relationship identifies the author defined end of a sequence of documents of which the current document is a node. TOP is a functional equivalent to END when only one is specified. When REL=END, the target document is the end of the sequence. When REV=END, the current document is the end of the sequence. If the hypertext link is specified with REL in a LINK element, an HTML user agent may present an icon in a tool bar.
END or LAST The END relationship identifies the author defined end of a sequence of documents of which the current document is a node. TOP is a functional equivalent to END when only one is specified. When REL=END, the target document is the end of the sequence. When REV=END, the current document is the end of the sequence. If the hypertext link is specified with REL in a LINK element, an HTML user agent may present an icon in a tool bar.
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.
rel=next The link references the next document to visit in a guided tour. It can be used, for example, to preload the next page.
REL=Next The link references the next document to visit in a guided tour.
NEXT The NEXT relationship identifies the next document in an author-defined sequence of documents, such as a linear book. When REL=NEXT, the target document is next after the current document. When REV=NEXT, the current document is next after the target. If the hypertext link is specified with REL in a LINK element, an HTML user agent may present an icon in a tool bar.
Prev Refers to the previous document in an ordered series of documents. Some user agents also support the synonym "Previous".
PREVIOUS or PREV The PREVIOUS relationship identifies the previous document in an author-defined sequence of documents, such as a linear book. When REL=PREVIOUS, the target document is previous to the current document. When REV=PREVIOUS, the current document is previous to the target. If the hypertext link is specified with REL in a LINK element, an HTML user agent may present an icon in a tool bar.
Prev Refers to the previous document in an ordered series of documents. Some user agents also support the synonym "Previous".
rel=previous The link references the previous document in a guided tour.
REL=Previous The link references the previous document in a guided tour.
PREVIOUS or PREV The PREVIOUS relationship identifies the previous document in an author-defined sequence of documents, such as a linear book. When REL=PREVIOUS, the target document is previous to the current document. When REV=PREVIOUS, the current document is previous to the target. If the hypertext link is specified with REL in a LINK element, an HTML user agent may present an icon in a tool bar.
REL=Up When the document forms part of a hierarchy, this link references the immediate parent of the current document.
rel=top The link references the top of a hierarchy, e.g. the first or cover page in a collection.
TOP or ORIGIN The TOP relationship identifies the logical top of a hierarchical tree of which the current document is a branch. BEGIN is a functional equivalent to TOP, if only one of these values is specified. When REL=TOP, the target document is the logical top node of the tree. When REV=TOP, the current document is the logical top of the tree. If the hypertext link is specified with REL in a LINK element, an HTML user agent may present an icon in a tool bar. NOTE: ORIGIN has been suggested as an alternative to TOP to provide metaphorical consistency with PARENT/CHILD/SIBLING. Comments are encouraged.
TOP or ORIGIN The TOP relationship identifies the logical top of a hierarchical tree of which the current document is a branch. BEGIN is a functional equivalent to TOP, if only one of these values is specified. When REL=TOP, the target document is the logical top node of the tree. When REV=TOP, the current document is the logical top of the tree. If the hypertext link is specified with REL in a LINK element, an HTML user agent may present an icon in a tool bar. NOTE: ORIGIN has been suggested as an alternative to TOP to provide metaphorical consistency with PARENT/CHILD/SIBLING. Comments are encouraged.
PARENT The PARENT relationship identifies the superior or container node. When REL=PARENT, the target document is the hierarchical parent, or container, of the current document. When REV=PARENT, the current document is the hierarchical parent, or container, of the target. If the hypertext link is specified with REL in a LINK element, an HTML user agent may present an icon in a tool bar.
CHILD The CHILD relationship identifies a subordinate or subdocument. Any document may have multiple CHILD documents within the same hierarchy. When REL=CHILD, the target document is a hierarchical child, or subdocument, of the current document. When REV=CHILD, the current document is the hierarchical child, or subdocument, of the target.
SIBLING The SIBLING relationship identifies a sibling in the current hierarchy. Any document may have multiple SIBLING documents within the same hierarchy. When REL=SIBLING, the target document is a child of a common parent, or a hierarchical peer of the current document. REL and REV have equivalent meanings for the SIBLING relationship.
Chapter Refers to a document serving as a chapter in a collection of documents.
Section Refers to a document serving as a section in a collection of documents.
Subsection Refers to a document serving as a subsection in a collection of documents.
Appendix Refers to a document serving as an appendix in a collection of documents.
Glossary Refers to a document providing a glossary of terms that pertain to the current document.
rel=glossary The link references a document providing a glossary of terms that are relevant to the current document.
REL=Glossary The link references a document providing a glossary of terms that pertain to the current document.
GLOSSARY The GLOSSARY relationship identifies a glossary. When REL=GLOSSARY, the target document is a glossary. When REV=GLOSSARY, the current document is a glossary. If the hypertext link is specified with REL in a LINK element, an HTML user agent may present an icon in a tool bar. A glossary may be directly presented as an HTML document which is organized and presented in a style reminiscent of a paper-based glossary. A glossary may also be accessed through an intermediary query mechanism. For example, the user highlights a word or phrase and presses the glossary button, thereby accessing the linked object and passing the highlighted text as an argument. The server returns the glossary entry relevant to the highlighted word.
DEFINITION The DEFINITION relationship identifies a definition of a term. Definitions may be, but are not necessarily, contained within a glossary. DEFINITION would most typically be specified on an A element, as it would specify a hypertext link from a term to its definition. HTTP
FOOTNOTE The FOOTNOTE relationship identifies a footnote. When REL=FOOTNOTE is specified on an A element, the anchor is a footnote marker and the target is a footnote. This can be used to link from the footnote marker (or a highlighted word, phrase, etc.) to an HTML document which contains the footnote text, or to a portion of the same document (see REV=FOOTNOTE). When REL=FOOTNOTE is specified on a LINK element, it can specify a hypertext link to a set of footnotes which are related to the current document, or to a set of end-notes. When REV=FOOTNOTE is specified on an A element, the anchor is a footnote; that is, the actual content of the footnote, as opposed to a footnote marker. In this case, the target specified by the HREF value, if any, is the footnote marker. It has been suggested that the combination of REV=FOOTNOTE and NAME=... on an A element may be used to imply that the enclosed content not be rendered until a link to it is explicitly traversed, at which time it can be presented in a popup window. This would allow for the inclusion of footnote text within a document that would not be visible until the reader wanted it to be presented. Developers of user agents are free to experiment with this proposed feature, but there is no requirement that it be implemented.
CITATION
The CITATION relationship identifies a bibliographic citation.
When REL=CITATION, the target is a bibliographic citation. The
anchor, in this case, may be a bibliographic entry. The anchor
may also be a reference, thus allowing the reader a way to
locate the citation:
... as described by Tim Berners-Lee
<A REL=CITATION HREF=#TBL>[1]</A>
...
When REV=CITATION, the anchor is a citation. Typically, the
anchor would also be enclosed within a CITE element as shown in
the example below. The example shown here also corresponds to
the previous example, serving as its target by use of the NAME
attribute.
... is described in Tim Berners-Lee's
<CITE><A NAME=TBL REV=CITATION HREF=./biblio/TBL > The
HyperText Markup Language </A> </CITE>
...
NOTE: an alternative (and preferred) approach would be to add a
URI-valued attribute (HREF?) to the HTML CITE element.
BIBLIOENTRY
The BIBLIOENTRY relationship identifies a bibliographic entry.
BIBLIOENTRY would most typically be specified on an A element,
as it would specify a hypertext link between a citation and a
bibliographic entry describing the citation. Example:
<A REL=BIBLIOENTRY HREF="biblio.html#V.Bush"><CITE>As We
May Think</CITE></A>
The resource identified by this link may take any form desired
by the author/publisher. A bibliographic entry may be presented
in the style of a paper-based bibliographic entry, or it may be
presented as the result of a database query.
BIBLIOGRAPHY The BIBLIOGRAPHY relationship identifies a bibliography. The resource identified by this link may take any form desired by the author/publisher. A bibliography may be presented as an HTML document which is organized and presented in a style reminiscent of a paper-based bibliography. A bibliography may also be presented as a form-based query into a bibliographic database. If the hypertext link is specified with REL in a LINK element, an HTML user agent may present a labeled icon in a tool bar.
Help Refers to a document offering help (more information, links to other sources information, etc.)
rel=help The link references a document offering help, e.g. describing the wider context and offering further links to relevant documents. This is aimed at reorienting users who have lost their way.
REL=Help The link references a document offering help, e.g. describing the wider context and offering further links to relevant documents. This is aimed at reorienting users who have lost their way.
NAVIGATOR The NAVIGATOR relationship identifies a navigational aid. When REL=NAVIGATOR, the target document is a navigational aid. A navigational aid may consist of a whole or partial Table of Contents, a list of related documents, an indication of the current document's location within a document hierarchy, or any other information which may be useful to the user. When REV=NAVIGATOR, the current document is a navigational aid. If the hypertext link is specified with REL in a LINK element, an HTML user agent may present an icon in a tool bar.
Contents Refers to a document serving as a table of contents. Some user agents also support the synonym ToC (from "Table of Contents").
REL=ToC The link references a document serving as a table of contents.
CONTENTS or TOC The TOC relationship identifies a Table of Contents. When REL=TOC, the target document is the Table of Contents for the current document, or for the collection of documents of which the current document is a member. When REV=TOC, the current document is a Table of Contents and the target document is a related document. When REL=TOC and REV=TOC it indicates that the current document is a Table of Contents and the target document is also a Table of Contents. Additional REL/REV values may be used to specify the relationship between the two, such as PARENT/CHILD. If the hypertext link is specified with REL in a LINK element, an HTML user agent may present an icon in a tool bar. Or, if capable, an HTML user agent may present the Table of Contents in a concurrent window or pane, highlighting the current document.
Contents Refers to a document serving as a table of contents. Some user agents also support the synonym ToC (from "Table of Contents").
rel=contents The link references a document serving as a table of contents.
CONTENTS or TOC The TOC relationship identifies a Table of Contents. When REL=TOC, the target document is the Table of Contents for the current document, or for the collection of documents of which the current document is a member. When REV=TOC, the current document is a Table of Contents and the target document is a related document. When REL=TOC and REV=TOC it indicates that the current document is a Table of Contents and the target document is also a Table of Contents. Additional REL/REV values may be used to specify the relationship between the two, such as PARENT/CHILD. If the hypertext link is specified with REL in a LINK element, an HTML user agent may present an icon in a tool bar. Or, if capable, an HTML user agent may present the Table of Contents in a concurrent window or pane, highlighting the current document.
Index Refers to a document providing an index for the current document.
rel=index The link references a document providing an index for the current document.
REL=Index The link references a document providing an index for the current document.
INDEX The INDEX relationship identifies an index. When REL=INDEX, the target document is an index for the current document, or for the collection of documents of which the current document is a member. When REV=INDEX, the current document is an index. Additional REL/REV values may be used to further specify the relationship between the two ends of the link. If the hypertext link is specified with REL in a LINK element, an HTML user agent may present an icon in a tool bar. An index may be presented as an HTML document which is organized and presented in a style reminiscent of a paper-based index. An index may also be presented as a form-based query into a full- text search database.
rel=search The link references a page for searching material related to a collection of pages.
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.
REL=Bookmark Bookmarks are used to provide direct links to key entry points into an extended document. The TITLE attribute may be used to label the bookmark. Several bookmarks may be defined in each document, and provide a means for orienting users in extended documents.
BOOKMARK The BOOKMARK relationship identifies a bookmark. Bookmarks are used to provide direct links to key entry points into an extended document. The TITLE attribute may be used to label the bookmark. Several bookmarks may be defined in each document, and provide a means for orienting users in extended documents.
Using LINK to include a Document Banner
The LINK element can be used with REL=Banner to reference
another document to be used as banner for this document. This
is typically used for corporate logos, navigation aids, and
other information which shouldn't be scrolled with the rest of
the document. For example:
<LINK REL=Banner HREF=banner.html>
The use of a LINK element in this way, allows a banner to be
shared between several documents, with the benefit of being
able to separately cache the banner. Rather than using a
linked banner, you can also include the banner in the document
itself, using the BANNER element.
BANNER The BANNER relationship identifies a document banner. When REL=BANNER, the target document is to be included within the current document as a banner. A banner is typically used for corporate logos, custom toolbars, and other information which would not typically be scrolled with the body of a document. When REV=BANNER, the current document is a banner. This may be used, in future, to provide error-checking or to prevent the use of a document as a banner unless it has been explicitly identified as a valid source. (Or not! Sorry, I was reaching for a useful meaning.) Compelling arguments have been made against the need for a REL=BANNER value, which is simply a special case of the INCLUDE mechanism.
Copyright Refers to a copyright statement for the current document.
rel=copyright The link references a copyright statement for the current document.
REL=Copyright The link references a copyright statement for the current document.
COPYRIGHT
The COPYRIGHT relationship identifies a hypertext link to a
copyright notice.
While it is arguable whether a copyright notice is required in
every HTML file to assert copyright protection on it, there is
clearly a desire to express copyright notice among a sufficient
portion of the user community to justify support.
A basic copyright notice for this document may simply state:
"Copyright 1995 by Murray C. Maloney". It may be desirable,
in place of or in addition to such a notice, to have a
hypertext link between each HTML document in a set and a single
copyright notice, as in the following examples:
<LINK REL=COPYRIGHT HREF="copyright.html">
<A REL=COPYRIGHT HREF="copyright.html">
Copyright 1995 by Murray C. Maloney</A>
TRADEMARK The TRADEMARK relationship identifies a hypertext link to a trademark notice. Usage is expected to be similar to that of the COPYRIGHT hypertext link.
DISCLAIMER The DISCLAIMER relationship identifies a hypertext link to a legal disclaimer. Usage is expected to be similar to that of the COPYRIGHT hypertext link. As with the copyright notice, there is no intention or expectation that such a link would be the only way to express a disclaimer.
PUBLISHER The PUBLISHER relationship identifies a hypertext link to a publisher. Usage is expected to be similar to that of the AUTHOR hypertext link.
EDITOR The EDITOR relationship identifies a hypertext link to an editor. Usage is expected to be similar to that of the AUTHOR hypertext link.
AUTHOR The AUTHOR relationship identifies a hypertext link to an author. The hypertext link may be to the author's home page, a biography, an audio or video clip, or an agent which sends mail to the author (e.g., using the `mailto:' scheme).
MADE The REV=MADE relationship has been used to identify the author or "maker" of an HTML document. Typical HREF values include a `mailto:' URI or the URL of the author's home page. Example: <A REV=MADE HREF="mailto:murray@sq.com">Author</A>
Made Defines who is the "maker" of this document. The HREF attribute should give an appropriate URL e.g. "mailto:dsr@hplb.hpl.hp.com". Browsers can use this to allow people to mail or post comments to the author of the document.
META The META relationship identifies a hypertext link to a node which contains meta-information related to the current document. This is intended to be a generalized meta-data relationship descriptor.
<!--================== The LINK Element ==================================-->
<!--
Relationship values can be used in principle:
a) for document specific toolbars/menus when used
with the LINK element in document head e.g.
start, contents, previous, next, index, end, help
b) to link to a separate style sheet (rel=stylesheet)
c) to make a link to a script (rel=script)
d) by stylesheets to control how collections of
html nodes are rendered into printed documents
e) to make a link to a printable version of this document
e.g. a postscript or pdf version (rel=alternate media=print)
-->
Stylesheet Refers to an external style sheet. See the section on external style sheets for details. This is used together with the link type "Alternate" for user-selectable alternate style sheets.
Link to an associated Style Sheet
The LINK element can be used with REL=StyleSheet to reference
a style sheet to be used to control the way the current
document is rendered. For example:
<LINK REL=StyleSheet HREF=housestyle.dsssl>
STYLESHEET The STYLESHEET relationship identifies a stylesheet. When REL=STYLESHEET, the target document is a stylesheet. When associated with a LINK element, the author/publisher is expressing an expectation that the target stylesheet will be applied by the HTML user agent. When associated with an A element, an HTML user agent may simply retrieve the target stylesheet for display, or it may launch a stylesheet editor with the target stylesheet. When REV=STYLESHEET, the current document is a stylesheet and the target document may be a demonstration of its use. In general, it is not anticipated that stylesheets will contain LINK or A elements, as they are not projected to be HTML documents.
Alternate Designates substitute versions for the document in which the link occurs. When used together with the hreflang attribute [1], 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).
TRANSLATION The TRANSLATION relationship specifies a translation to another language. When REL=TRANSLATION, the target is a translation to another language. This value will most typically be used with the LINK element, in combination with specification of the target document's language as a LANG attribute value. Presumably, REL=TRANSLATION can be used with the A element to specify a translation of a document fragment, such as a phrase in a foreign language. When REV=TRANSLATION, the current document, or document fragment, is a translation of the target.
The "node" and "path" values mentioned in the HTML 3.0 Draft DTD have not been included. Also, three link types included in Hypertext Links in HTML ([Hypertext Links(draft):4]) have not found their way into this document; two of them are reserved keywords, "hotlist" and "urc", and the other, "pointer", just hasn't been included.
[1]The specification reads "the lang attribute", but I believe this to be in error because the lang attribute is defined to describe the nature of the element itself whereas the hreflang attribute is defined to describe the linked resource (HTML4.01:12.1.5 - Internationalization and links). Furthermore, an entire section of examples (HTML4.01:12.3.3 - Links and search engines) is devoted to using alternate for accessing a different language version with hreflang, not lang, indicating the language.