<refentry xmlns="http://docbook.org/ns/docbook"
          xmlns:xlink="http://www.w3.org/1999/xlink"
          xmlns:xi="http://www.w3.org/2001/XInclude"
          xmlns:src="http://nwalsh.com/xmlns/litprog/fragment"
          xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
          version="5.0" xml:id="activate.external.olinks">
<refmeta>
<refentrytitle>activate.external.olinks</refentrytitle>
<refmiscinfo class="other" otherclass="datatype">boolean</refmiscinfo>
</refmeta>
<refnamediv>
<refname>activate.external.olinks</refname>
<refpurpose>Make external olinks into active links</refpurpose>
</refnamediv>

<refsynopsisdiv>
<src:fragment xml:id="activate.external.olinks.frag">
<xsl:param name="activate.external.olinks" select="1"/>
</src:fragment>
</refsynopsisdiv>

<refsection><info><title>Description</title></info>

<para>If <parameter>activate.external.olinks</parameter> is nonzero
(the default), then any olinks that reference another document
become active links that can be clicked on to follow the link.
If the parameter is set to zero, then external olinks
will have the appropriate link text generated, but the link is
not made active.  Olinks to destinations in
the current document remain active.</para>

<para>To make an external olink active for HTML
outputs, the link text is wrapped in an <tag>a</tag>
element with an <tag>href</tag> attribute. To
make an external olink active for FO outputs, the link text is
wrapped in an <tag>fo:basic-link</tag> element with an
<tag>external-destination</tag> attribute.</para>

<para>This parameter is useful when you need external olinks
to resolve but not be clickable. For example, if documents
in a collection are available independently of each other,
then having active links between them could lead to
unresolved links when a given target document is missing.</para>

<para>The epub stylesheets set this parameter to zero by default
because there is no standard linking mechanism between Epub documents.</para>

<para>If external links are made inactive, you should
consider setting the
stylesheet parameter <parameter>olink.doctitle</parameter>
to <literal>yes</literal>. That will append the external document's
title to the link text, making it easier for the user to
locate the other document.</para>

<para>An olink is considered external when the
<parameter>current.docid</parameter> stylesheet parameter
is set to some value, and the olink's <tag>targetdoc</tag>
attribute has a different value. If the two values
match, then the link is considered internal.  If the
<parameter>current.docid</parameter> parameter is blank, or
the <tag>olink</tag> element does not have a <tag>targetdoc</tag> attribute,
then the link is considered to be internal and will become
an active link.</para>

<para>See also <parameter>olink.doctitle</parameter>,
<parameter>prefer.internal.olink</parameter>.</para>

</refsection>
</refentry>
