public abstract class DocumentFragment
extends Node
Core Dom Level 2 Interface. DocumentFragment is a "lightweight" or "minimal" Document 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
Document object could fulfill this role, a Document object can potentially be a heavyweight
object, depending on the underlying implementation. What is really needed for this is a very
lightweight object. DocumentFragment is such an object.
Furthermore, various operations -- such as inserting nodes as children of another Node -- may
take DocumentFragment objects as arguments; this results in all the child nodes of the
DocumentFragment being moved to the child list of this node.
The children of a DocumentFragment node are zero or more nodes representing the tops of any
sub-trees defining the structure of the document. DocumentFragment nodes do not need to be
well-formed XML documents (although they do need to follow the rules imposed upon well-formed
XML parsed entities, which can have multiple top nodes). For example, a DocumentFragment might
have only one child and that child node could be a Text node. Such a structure model represents
neither an HTML document nor a well-formed XML document.
When a DocumentFragment is inserted into a Document (or indeed any other Node that may take
children) the children of the DocumentFragment and not the DocumentFragment itself are inserted
into the Node. This makes the DocumentFragment very useful when the user wishes to create nodes
that are siblings; the DocumentFragment acts as the parent of these nodes so that the user can
use the standard methods from the Node interface, such as insertBefore and appendChild.
Note that this object is implemented and supported by the web
browser and results of its use may vary.