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NodeFilter

To create a

NodeIterator

object, use the

createNodeIterator()

method of the

document

object. This

method accepts four arguments:

root

— the node in the tree that you wish to start searching from

whatToShow

— a numerical code indicating which nodes should be visited

filter

—a

NodeFilter

object to determine which nodes to ignore

entityReferenceExpansion

— a Boolean value indicating whether entity references should

be expanded

The

whatToShow

argument determines which nodes to visit by applying one or more of the following

constants:

NodeFilter.SHOW_ALL

— show all node types

NodeFilter.SHOW_ELEMENT

— show element nodes

NodeFilter.SHOW_ATTRIBUTE

— show attribute nodes

NodeFilter.SHOW_TEXT

— show text nodes

NodeFilter.SHOW_CDATA_SECTION

— show CData section nodes

NodeFilter.SHOW_ENTITY_REFERENCE

— show entity reference nodes

NodeFilter.SHOW_ENTITY

— show entity nodes

NodeFilter.SHOW_PROCESSING_INSTRUCTION

— show PI nodes

NodeFilter.SHOW_COMMENT

— show comment nodes

NodeFilter.SHOW_DOCUMENT

— show document nodes

NodeFilter.SHOW_DOCUMENT_TYPE

— show document type nodes

NodeFilter.SHOW_DOCUMENT_FRAGMENT

— show document fragment nodes

NodeFilter.SHOW_NOTATION

— show notation nodes

You can combine multiple values by using the bitwise OR operator:

var iWhatToShow = NodeFilter.SHOW_ELEMENT | NodeFilter.SHOW_TEXT;

The filter argument of

createNodeIterator()

can be used to specify a custom

NodeFilter

object, but

can also be left

null

if you don’t want to use it.

To create a simple

NodeIterator

that visits all node types, use the following:

var iterator = document.createNodeIterator(document, NodeFilter.SHOW_ALL, null,

false);

To move forward and backward in the search, use the

nextNode()

and

previousNode()

methods:

var node1 = iterator.nextNode();

var node2 = iterator.nextNode();

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