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<?xml version="1.0" encoding="UTF-8"?>
<!--[ DocumentFragment object description ]-->
<!-- $Date: 2001/11/26 22:34:22 $ $Revision: 1.1.1.1 $ -->
<interface name="DocumentFragment" inherits="Node" id="ID-B63ED1A3">
<descr><p><code>DocumentFragment</code> is a "lightweight" or "minimal"
<code>Document</code> object. It is very common to want to be able to
extract a portion of a document's tree or to create a new fragment of a
document. Imagine implementing a user command like cut or rearranging a
document by moving fragments around. It is desirable to have an object
which can hold such fragments and it is quite natural to use a Node for
this purpose. While it is true that a <code>Document</code> object could
fulfill this role, a <code>Document</code> object can potentially be a
heavyweight object, depending on the underlying implementation. What is
really needed for this is a very lightweight object.
<code>DocumentFragment</code> is such an object.</p>
<p>Furthermore, various operations -- such as inserting nodes as children
of another <code>Node</code> -- may take <code>DocumentFragment</code>
objects as arguments; this results in all the child nodes of the
<code>DocumentFragment</code> being moved to the child list of this
node.</p>
<p>The children of a <code>DocumentFragment</code> node are zero or more
nodes representing the tops of any sub-trees defining the structure of
the document. <code>DocumentFragment</code> nodes do not need to be
<termref def="dt-well-formed">well-formed XML documents</termref> (although they do need to follow the rules
imposed upon well-formed XML parsed entities, which can have multiple top
nodes). For example, a <code>DocumentFragment</code> might have only one
child and that child node could be a <code>Text</code> node. Such a
structure model represents neither an HTML document nor a well-formed XML
document.</p>
<p>When a <code>DocumentFragment</code> is inserted into a
<code>Document</code> (or indeed any other <code>Node</code> that may
take children) the children of the <code>DocumentFragment</code> and not
the <code>DocumentFragment</code> itself are inserted into the
<code>Node</code>. This makes the <code>DocumentFragment</code> very
useful when the user wishes to create nodes that are <termref def="dt-sibling">siblings</termref>; the
<code>DocumentFragment</code> acts as the parent of these nodes so that
the user can use the standard methods from the <code>Node</code>
interface, such as <code>insertBefore</code> and
<code>appendChild</code>.</p>
</descr>
</interface>
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