Learning JavaScript

Modifying the Tree

The document is the owner/parent of all page elements. Because of this, most factory methods to create instances of new elements are methods on the Core document object. The Node, though, maintains the navigation within the Core API. This supports the hierarchical structure of the document tree, in which each node has a relationship to other nodes, and navigation follows this natural structure: parent/child, sibling/sibling. Finally, the Element provides a way to access elements within context in order to apply changes to nested elements. All three are essential objects when it comes to modifying the document tree.

The document factory methods, and the type of Core objects they create, are listed in Table 10-1. This also provides a brief introduction to several of the Core objects.

Table 10-1. Factory methods of the Document object

Method	Object created	Description
createElement(tagname)	Element	Creates an element that is cast to the specific tag
createDocumentFragment	DocumentFragment	The DocumentFragment is a lightweight document, used when extracting a section of the document tree
createTextNode(data)	Text	Holds any text in the page
createComment(data)	Comment	XML comment
createCDATASection(data)	CDATASection	CDATA section
createProcessingInstructions(target,data)	ProcessingInstruction	XML processing instruction
createAttribute(name)	Attr	Element attribute
createEntityReference(name)	EntityReference	Placeholder for an element to be placed later
createElementNS ...