<fn>
The <fn>
element is a footnote used to annotate text with notes
that are inappropriate for inline inclusion. It is also used to indicate the source for facts or
other material used in the text.
- A footnote with no specified
@id
attribute is a single-use footnote. Upon output, it generates a number as a superscript "callout" that is linked to the placement of the footnote, such as at the bottom of the immediate printed page or at the end of an online article. If a character is specified in the@callout
attribute for the footnote, that character is used as the superscript "callout" that is linked to the placement of the footnote. - A footnote that specifies an
@id
attribute is a use-by-reference footnote. Upon output, it does not appear anywhere unless it has been referenced using an<xref>
with the@type
attribute set to "fn". - Ordinarily, a footnote in one topic can't be referenced in another topic. The previous
behaviors are local to each topic. But by using the conref mechanism, you can create a new
copy of another topic's footnote within the local topic where it will then follow these behaviors:
- If you use
<fn conref="file.dita#topic/thatid"></fn>
all by itself, the result will be the same as the single-use footnote entered literally in the same location. That is, it creates a local copy of the footnote with no local@id
attribute, so it uses the behavior from the first bullet above. - If you use
<fn conref="file.dita#topic/thatid" id="thisid"></fn>
, followed by<xref href="#thistopic/thisid" type="fn"/>
, the result will be the same as the use-by-reference model described in the second bullet. That is, the<fn>
element creates a local copy of the footnote with an id of "thisid"; that local copy is then referenced by the<xref>
element.
- If you use
The details of footnote processing and styling are implementation and/or stylesheet
dependent. For example, a tool that renders DITA as PDF might
lack support for the @callout
attribute, or footnotes might be collected as endnotes for certain types of
publications.
Content models
See appendix for information about this element in OASIS document type shells.
Inheritance
- topic/fn
Example
<fn>
element, with no @id
and no
@callout
attribute. In that case, markup such as the
following:The memory storage capacity of the computer is
2 GB<fn>A GB (gigabyte) is equal to
1000 million bytes</fn> with error correcting support.
might produce output similar to the following:The memory storage capacity of the computer is 2 GB1 with error correcting support.
......
1 A GB (gigabyte) is equal to 1000 million bytes
----- [bottom of page] -----------------------------------------------------------------
@callout
attribute. It is marked up as
follows:The memory storage capacity of the computer is
2 GB<fn callout="#">A GB (gigabyte) is equal to
1000 million bytes</fn> with error correcting support.
That
DITA markup might produce output similar to the following:The memory storage capacity of the computer is 2 GB# with error correcting support.
......
# A GB (gigabyte) is equal to 1000 million bytes
----- [bottom of page] -----------------------------------------------------------------
@id
on a
footnote, and then references that @id
multiple times. The DITA markup looks
like
this:I like pets. <fn id="reuse-fn">This is the name of an animal.</fn>
At my house, I have a dog<xref href="#topic/reuse-fn" type="fn"/>, a
cat<xref href="#topic/reuse-fn" type="fn"/>, and a
llama<xref href="#topic/reuse-fn" type="fn"/>.
and
might produce output similar to the following:I like pets. At my house, I have a dog1, a cat1, and a llama1.
......
1This is the name of an animal.
----- [bottom of page] -----------------------------------------------------------------
Attributes
The following attributes are available on this element: Universal attribute group, outputclass, and the attribute defined below.
@callout
- Specifies what character is used for the
footnote link, for example a number or an alpha
character. The attribute can also specify a short string of
characters. When no
@callout
value is specified, footnotes are typically numbered.
@datatype
- Available for describing the type of data contained in the value attribute for this metadata element. The default value is the empty string "".