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<?xml version="1.0" encoding="UTF-8"?>
<!-- $Date: 2001/11/26 22:34:22 $ $Revision: 1.1.1.1 $ -->
<!--[ Attr object description ]-->
<interface name="Attr" inherits="Node" id="ID-637646024">
<descr><p>
The <code>Attr</code> interface represents an attribute in an <code>Element</code> object.
Typically the allowable values for the attribute are defined in a document
type definition.</p>
<p><code>Attr</code> objects inherit the <code>Node</code>
interface, but since they are not actually child nodes of the element
they describe, the DOM does not consider them part of the document
tree. Thus, the <code>Node</code> attributes <code>parentNode</code>,
<code>previousSibling</code>, and <code>nextSibling</code> have a
<code>null</code> value for <code>Attr</code> objects. The DOM takes the
view that attributes are properties of elements rather than having a
separate identity from the elements they are associated with;
this should make it more efficient to implement
such features as default attributes associated with all elements of a
given type. Furthermore, <code>Attr</code>
nodes may not be immediate children of a <code>DocumentFragment</code>.
However, they can be associated with <code>Element</code> nodes contained within
a <code>DocumentFragment</code>.
In short, users and implementors of the DOM need to be aware that
<code>Attr</code> nodes have some things in
common with other objects inheriting the <code>Node</code> interface,
but they also are quite distinct.</p>
<p> The attribute's effective value is determined as follows: if this
attribute has been explicitly assigned any value, that value is the
attribute's effective value; otherwise, if there is a declaration for
this attribute, and that declaration includes a default value, then
that default value is the attribute's effective value; otherwise, the
attribute does not exist on this element in the structure model until
it has been explicitly added. Note that the <code>nodeValue</code>
attribute on the <code>Attr</code> instance can also be used to
retrieve the string version of the attribute's value(s). </p>
<p>In XML, where the value of an attribute can contain entity references,
the child nodes of the <code>Attr</code> node provide a representation in
which entity references are not expanded. These child nodes may be either
<code>Text</code> or <code>EntityReference</code> nodes. Because the
DOM Core is not aware of attribute types, it treats all attribute values
as simple strings, even if the DTD or schema declares them as having
<termref def="dt-tokenized">tokenized</termref> types.
</p>
</descr>
<attribute type="DOMString" readonly="yes" name="name" id="ID-1112119403">
<descr><p>Returns the name of this attribute. </p></descr>
</attribute>
<attribute type="boolean" readonly="yes" name="specified" id="ID-862529273">
<descr><p>If this attribute was explicitly given a value in the original
document, this is <code>true</code>; otherwise, it is <code>false</code>.
Note that the implementation is in charge of this attribute, not the
user. If the user changes the value of the attribute (even if it ends up
having the same value as the default value) then the <code>specified</code>
flag is automatically flipped to <code>true</code>. To re-specify the
attribute as the default value from the DTD, the user must delete the
attribute. The implementation will then make a new attribute available
with <code>specified</code> set to <code>false</code> and the default value
(if one exists).</p>
<p>In summary:
<ulist>
<item><p> If the attribute has an assigned value in the document then
<code>specified</code> is <code>true</code>, and the value is the
assigned value.
</p></item>
<item><p> If the attribute has no assigned value in the document and has
a default value in the DTD, then <code>specified</code> is <code>false</code>,
and the value is the default value in the DTD.</p></item>
<item><p> If the attribute has no assigned value in the document and has
a value of #IMPLIED in the DTD, then the attribute does not appear
in the structure model of the document.
</p></item>
<item><p>If the <code>ownerElement</code> attribute is
<code>null</code> (i.e. because it was just created or was set to
<code>null</code> by the various removal and cloning operations)
<code>specified</code> is <code>true</code>.</p>
</item>
</ulist>
</p>
</descr>
</attribute>
<attribute type="DOMString" name="value" id="ID-221662474">
<descr><p>On retrieval, the value of the attribute is returned as a
string. Character and general entity references are replaced with their
values. See also the method <code>getAttribute</code> on the
<code>Element</code> interface.</p>
<p>On setting, this creates a <code>Text</code> node with the unparsed
contents of the string. I.e. any characters that an XML processor would
recognize as markup are instead treated as literal text.
See also the method <code>setAttribute</code> on the
<code>Element</code> interface.</p></descr>
<setraises>
<exception name="DOMException">
<descr><p>NO_MODIFICATION_ALLOWED_ERR: Raised when the node is
readonly.</p></descr>
</exception>
</setraises>
</attribute>
<!-- ****** DOM Level 2 additions ****** -->
<attribute name="ownerElement" type="Element" readonly="yes"
id="Attr-ownerElement" since="DOM Level 2">
<descr><p>The <code>Element</code> node this attribute is attached to or
<code>null</code> if this attribute is not in use.</p></descr>
</attribute>
</interface>
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