The
ref element represents a reference to an internal or external entity.
The referenced entity is not required to be resolvable or includable in a processing or rendering context: the
ref element may point to conceptual or physical items.
The
ref element may employ attributes from the
xlink.attrib
attributes collection to specify the nature of the hyperlink, including or excluding expressions of link activation behavior.
IDREF link relationships may also be established using the
ref
attribute, but not in conjunction with the
xlink attributes collection.
Usage details available in the Usage Details section.
Usage Example
<index>
<entry>origin of fruit-trees, <ref ref="page29">29</ref>, <ref ref="page39">39</ref>.</entry>
</index>
Allowed parents
annoref,
annotation (block variant),
annotation (phrase variant),
m:annotation-xml,
aside,
block,
caption,
citation (block variant),
citation (phrase variant),
d,
definition,
description (block variant),
description (phrase variant),
emph,
expansion,
h,
hd,
hpart,
item,
ln,
d:longdesc,
meta,
note (block variant),
note (phrase variant),
noteref,
object (block variant),
object (phrase variant),
p,
ssml:phoneme,
ssml:prosody,
quote (block variant),
quote (phrase variant),
its:rb,
ref,
its:rt,
s,
ssml:say-as (phrase variant),
ssml:say-as (text variant),
d:simplifiedLanguageDescription,
span,
ssml:sub,
d:summary,
td,
term,
th and
d:tour
Allowed children
This element may contain text.
This element may contain the following children: abbr,
annoref,
ssml:break,
char,
code,
d,
definition,
emph (text variant),
emph (phrase variant),
expansion,
rend:linebreak,
ln,
m:math,
name,
note,
noteref,
num,
object (text variant),
object (phrase variant),
pagebreak,
ssml:phoneme (text variant),
ssml:phoneme (phrase variant),
ssml:prosody (text variant),
ssml:prosody (phrase variant),
ref,
its:ruby,
s,
ssml:say-as (text variant),
ssml:say-as (phrase variant),
span (phrase variant),
span (text variant),
sub,
ssml:sub (text variant),
ssml:sub (phrase variant),
sup,
term,
time,
ssml:token (text variant),
ssml:token (phrase variant) and
w
Content model and additional requirements
optional attributes:
@about,
@by,
@class,
@content,
@continuation,
@datatype,
@desc,
@its:dir,
@its:translate,
@property,
@rel,
@resource,
@rev,
@role,
@ssml:onlangfailure,
@typeof,
@xml:base,
@xml:id,
@xml:lang and
@xml:spacea choice of
end of choice
one or more of
a choice of either one of the 42 elements:
abbr,
annoref,
char,
code,
d,
definition,
emph,
emph,
expansion,
its:ruby,
ln,
m:math,
name,
note,
noteref,
num,
object,
object,
pagebreak,
ref,
rend:linebreak,
s,
span,
span,
ssml:break,
ssml:break,
ssml:phoneme,
ssml:phoneme,
ssml:prosody,
ssml:prosody,
ssml:say-as,
ssml:say-as,
ssml:sub,
ssml:sub,
ssml:token,
ssml:token,
sub,
sup,
term,
time,
w or
wor text
end of choice
Note that in addition to restrictions presented in the content model above,
use of this element must also respect the following requirements:
- The
ref element must not contain descendant
ref elements.
- The
ref element must neither be empty nor contain only whitespace.
Such requirements take precedence over any conflicting statements in the
content model or in the lists above of allowed children and parents.
Namespace
http://www.daisy.org/ns/z3998/authoring/
Usage Details
The
ref element can be used with the
ref attribute to link to resources that are contained within the current document. Typical examples of this kind of usage occur
in indexes and tables of contents, where the
ref element is used to link to a corresponding page number or location:
<toc>
<entry>INTRODUCTION <ref ref="p1">Page 1</ref></entry>
</toc>
It is not necessary for the
ref element to point to a location, even when used for page references as in the above example (e.g. if alternate methods of
linking are expected in outputs). Marking the references without linking them can still be useful for formatting leader lines
between the text and reference in a table of contents entry, for example.
Not all references are to internal locations, of course, and the
ref elements allows attributes from the XLink feature to be attached instead for such situations:
<p>For more information, refer to the
<ref xlink:href="http://en.wikipedia.org/wiki/Charles_Darwin">wikipedia article on Darwin</ref>.</p>
It is also not necessary for the
ref element to point to an electronic resource at all. The element could be used to tag the coordinates of a physical location
or object, for example:
<p>San Cristóbal Island, the first Darwin visited, is located at
<ref><num role="coordinate">0°48′S</num> <num class="coordinate">89°24′W</num></ref>.</p>