A notation for creating XML elements that can function as links,
called linking elements. For example:
<catalog xmlns:xlink="http://www.w3.org/1999/xlink">
...
<course xlink:type="simple"
xlink:href="http://www.keller.com/xml/index.htm">
XML Accelerated Technical Training
</course>
...
</catalog>
You create linking elements by specifying certain attributes
that belong to the xlink namespace, such as xlink:type
(we will see these in detail in the next sections).
The xlink namespace must be declared.
XLink
is a language, not an application.
It describes relationships between "resources".
An actual application is necessary to do something
useful with the linking elements thus described.
Resources can be XML documents or parts of them
or points within them:
A local resource is the linking element itself.
A remote resource is what the element "points" to,
whether it is in a remote file or within the same XML document.
XLink can be used together with
XPointer,
which is a language for addressing parts of an XML document.
XPointer is based on
XPath,
which is used by XSLT.
We have already seen some of XPath's capabilities in the
Pattern Matching section of
the chapter on XSL.
XLink is not currently supported by any browser or other applications.
Therefore, the labs in this course are implemented using
XSL stylesheets "behind the scenes".
Although this method is not truly "XLink-conformant", it serves
to illustrate many of its features.
