Link

Link End Tag: Omitted Support Key: 2 \| 3 \| 3.2 \| 4 \| IE3B1 \| M3 \| N4B2 \| O3.5	What is it? Attributes Tag Example	Parent/Content Model Tips & Tricks Browser Peculiarities
= Index DOT Html by Brian Wilson [bloo@blooberry.com] =

Main Index | Element Tree | Element Index | HTML Support History

What is it?: The Link element is a special HEAD element utilizing many of the same attributes as the Hyperlink element [A]. It indicates a relationship between the current document and some other object. A document may have any number of LINK elements which can indicate authorship, related indices and glossaries, older or more recent versions, document hierarchy, associated resources such as style sheets, etc. Servers may also allow links to be added to a document by those who do not have the right to alter the body portion of a document. The popular browsers are just beginning to support this element, which has been in the HTML specifications for some time.

Some uses for LINK
Many of the following keywords are taken from the expired HTML 3.0 Draft. They describe a proposed standard set of relationships for use in documents. Details of browser support and examples are further down.
REL=Bookmark: These 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.
REL=Copyright: References a copyright statement for the current document.
REL=Fontdef: References a downloadable font definition file.
REL=Glossary: References a document providing a glossary of terms that pertain to the current document.
REL=Help: 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=Home: References a home page or the top of some hierarchy.
REL=Index: References a document providing an index for the current document.
REL=Next: References the next document to visit in a document structure or guided tour.
REL=Previous: References the previous document in a document structure or guided tour.
REL=StyleSheet: References an external Style Sheet [-->Index DOT Css] which is used to control the way the current document is rendered.
REL=ToC: References a document serving as a table of contents.
REL=Up: If the document is part of a hierarchy, this references the immediate parent of the current document.
Defining document specific toolbars
[ IE | M3 | N | O ]: The LINK element can be used to define a toolbar of navigation buttons or an equivalent mechanism such as menu items. Many of the values for the REL attribute could be reserved for this purpose (such as Home, Next, Previous, etc.); Example:
<link TITLE="Here is my home page" REL="HOME" HREF="myhome.htm">
Link to an associated Style Sheet
[ IE3B1 | M | N4B2 | O3.5 ]: The LINK element can be used with REL=StyleSheet to reference an external Style Sheet which is used to control the way the current document is rendered.; Example:
<link REL="STYLESHEET" HREF="http://www.company.com/mystyles.css" TYPE="text/css">
Link to a Font Definition file
[ IE | M | N4 | O3.5 ]: The LINK element can be used with REL=Fontdef to reference a downloadable font definition file.; Example:
<link REL="FONTDEF" SRC="http://www.example.com/fonts/downloadfont.pfr">

Common Attributes
%Core%: 2 | 3 | 3.2 | 4 | IE4 | M3 | N | O
%Events%: 2 | 3 | 3.2 | 4 | IE | M | N | O
%Language%: 2 | 3 | 3.2 | 4 | IE | M | N | O
Specific Attributes
Charset
2 | 3 | 3.2 | 4 | IE | M | N | O: Required? No; Description:
This attribute indicates the character encoding of the destination resource of the hyperlink.; Values:
A recognized RFC 2045 language character set string. Default is ISO-8859-1.
Disabled
2 | 3 | 3.2 | 4 | IE4 | M | N | O: Required? No; Description:
This is a stand-alone attribute which indicates the linked dependency is initially non-functional.; Values: NA
Href
2 | 3 | 3.2 | 4 | IE3B1 | M3 | N4B2 | O3.5: Required? No; Description:; This attribute indicates the URL of a document linked to the current document through relationships established by the other attributes of this tag.; Values: Relative or absolute URLs.
Hreflang
2 | 3 | 3.2 | 4 | IE | M | N | O: Required? No; Description:
This attribute specifies the base language of the resource indicated in the HREF attribute.; Values: RFC 1766 values.
Media
2 | 3 | 3.2 | 4 | IE4 | M | N | O3.5: Required? No; Description:
This attribute is a keyword representing the intended rendering destination for the style sheet definitions. Multiple destinations are given delimited by commas.; Values:
screen [DEFAULT] - style information should be used for rendering to computer screens.
print - style information should be used for rendering to page-centric devices, ie: printed paper or print preview screen modes.
projection - style information should be used for rendering to transparent projected media devices.
braille - style information should be used for rendering to braille devices.
speech - style information should be used for rendering to speech synthesizers.
all - style information should be used for rendering to all devices.
Rel
2 | 3 | 3.2 | 4 | IE3B1 | M3 | N4B2 | O3.5: Required? No; Description:; The REL attribute is meant to give the relationship(s) described between the current document and the document specified by the HREF attribute.; Values: A whitespace separated list of relationship names.
Rev
2 | 3 | 3.2 | 4 | IE4 | M3 | N | O: Required? No; Description:; The REV attribute is basically meant to be the same as the REL attribute, but the semantics of the relationship are in the reverse direction. A link from A to B with REL="X" expresses the same relationship as a link from B to A with REV="X". A LINK tag may have both REL and REV attributes.; Values: A whitespace separated list of relationship names.
Src
2 | 3 | 3.2 | 4 | IE | M | N4 | O: Required? No; Description:
This attribute indicates the URL of a downloadable font definition file.; Values: Relative or absolute URLs.
Target
2 | 3 | 3.2 | 4 | IE | M | N | O: Required? No; Description:
This attribute specifies the named frame for the browser to display the linked resource if activated by the system or user.; Values: The TARGET reserved names apply.
Type
2 | 3 | 3.2 | 4 | IE3B1 | M | N4B2 | O: Required? No; Description:; This attribute represents the MIME type of the linked resource.; Values: (wrt style sheet usage) text/css, text/javascript

Example: <html>
<head>
     <title>Document Title</title>
     <link TITLE="Here is my home page" REL="HOME" HREF="myhome.htm">
     <link REL="STYLESHEET" HREF="http://www.company.com/mystyles.css" TYPE="text/css">
</head>
<body>
     Document content goes here.
</body>
</html>

Parent Model: <head>
Content Model: This element does not accept any content.

Tips & Tricks

The Mosaic implementation of the LINK element is not widely supported, even though many of the concepts for it have existed in HTML since version 2.0. Its use does not harm a document in any way, but it would be best not to rely on this as a sole navigation scheme until wider support exists.
Remember to use the TYPE attribute in relation to the use of the LINK element for Style Sheet purposes. With the advent of Netscape's Javascript Accessible Style Sheets, it never hurts to be explicit as to which style sheet language is being used.
The wide implementation of Style Sheets has begun with Internet Explorer 3.0 and has continued with its debut in Netscape version 4.0 and Opera 3.5. These browsers represent a fair amount of the total browser market, so use of CSS is not discouraged (it doesn't hurt that CSS is backward compatible with non-CSS browsers.)

Browser Peculiarities

Mosaic supports the LINK element beginning in its 3.0 versions. All LINK REL navigation relationships will be rendered in a separate pane of the browser window (it sounds like one of the original ideas for a common navigation bar.)
Internet Explorer 3.0 Beta 1 did not automatically register the MIME type for Style Sheets, so if you're using a linked style sheet, the server administrator on the user's site would have to register the "text/css" type on the server. This problem was fixed in later Internet Explorer versions.
Netscape 4.0 Beta 2 assumed a default MIME type for style sheets to be 'text/javascript' for Javascript accessible style sheets. This was fixed in beta 3 to the accepted 'text/css' default.
Internet Explorer 4.0 and 5.0 only support the 'screen', 'print' and 'all' Media attribute values.
Opera 3.5 only supports the 'screen', and 'all' Media attribute values.
Internet Explorer 3.0 only allowed for a single LINK or STYLE block. Only the last one specified in the document is used.
Netscape, Opera and Internet Explorer 4.0+ merge/cascade multiple stylesheet LINK elements.
Although Internet Explorer 4.0 and above has access to the REV attribute through the DOM, it does not appear to do anything with this information.