Calling insertBefore on Documents

 

If the current node is a document, calling insertBefore has the following results, depending on the value of the newChild parameter.

Node type passed in newChild	Result
NODE_ATTRIBUTE, NODE_CDATA_SECTION, NODE_DOCUMENT, NODE_ENTITY, NODE_ENTITY_REFERENCE, NODE_NOTATION, NODE_TEXT	Returns an error. These nodes are not valid as children of a document node.
NODE_COMMENT, NODE_PROCESSING_INSTRUCTION	Inserts newChild and returns newChild.
NODE_ELEMENT	Inserts newChild and returns newChild. By definition, an XML document (the Document node) can have only a single child. Therefore, an error is returned if the Document node already has a child.
NODE_DOCUMENT_FRAGMENT	Inserts the children of the document fragment (in newChild) and returns newChild. The insert operations are subject to the rules for child nodes and can fail if the document fragment children represent node types that cannot be inserted.
NODE_DOCUMENT_TYPE	Returns an error. The document type is read-only.