[−][src]Trait xml_dom::level2::DocumentFragment
This corresponds to the DOM DocumentFragment
interface (current unsupported).
Specification
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
.