dfn
elementdfn
element descendants.title
attribute has special semantics on this
element.HTMLElement
.The dfn
element represents
the defining instance of a term. The paragraph, description list group, or section
that is the nearest ancestor of the dfn
element must also contain the definition(s)
for the term given by the
dfn
element.
Defining term: If the
dfn
element has a title
attribute, then the
exact value of that attribute is the term being defined. Otherwise,
if it contains exactly one element child node and no child
Text
nodes, and that child element is an abbr
element with a title
attribute, then the exact value of
that attribute is the term being defined. Otherwise, it is
the exact textContent
of the dfn
element that gives the term being
defined.
If the title
attribute of the dfn
element is present, then it must contain
only the term being defined.
The title
attribute of ancestor elements does not
affect dfn
elements.
An a
element that links to a dfn
element represents an instance of the term
defined by the dfn
element.
In the following fragment, the term "Garage Door Opener" is first defined in the first paragraph, then used in the second. In both cases, its abbreviation is what is actually displayed.
<p>The <dfn><abbr title="Garage Door Opener">GDO</abbr></dfn> is a device that allows off-world teams to open the iris.</p> <!-- ... later in the document: --> <p>Teal'c activated his <abbr title="Garage Door Opener">GDO</abbr> and so Hammond ordered the iris to be opened.</p>
With the addition of an a
element, the reference can be made
explicit:
<p>The <dfn id=gdo><abbr title="Garage Door Opener">GDO</abbr></dfn> is a device that allows off-world teams to open the iris.</p> <!-- ... later in the document: --> <p>Teal'c activated his <a href=#gdo><abbr title="Garage Door Opener">GDO</abbr></a> and so Hammond ordered the iris to be opened.</p>