Document.createNodeIterator() - Web APIs 编辑

Returns a new NodeIterator object.

Syntax

const nodeIterator = document.createNodeIterator(root[, whatToShow[, filter]]);

Values

root

The root node at which to begin the NodeIterator's traversal.

whatToShow Optional

Is an optional unsigned long representing a bitmask created by combining the constant properties of NodeFilter. It is a convenient way of filtering for certain types of node. It defaults to 0xFFFFFFFF representing the SHOW_ALL constant.

Constant	Numerical value	Description
NodeFilter.SHOW_ALL	-1 (that is the max value of unsigned long)	Shows all nodes.
NodeFilter.SHOW_ATTRIBUTE	2	Shows attribute Attr nodes. This is meaningful only when creating a TreeWalker with an Attr node as its root. In this case, it means that the attribute node will appear in the first position of the iteration or traversal. Since attributes are never children of other nodes, they do not appear when traversing over the document tree.
NodeFilter.SHOW_CDATA_SECTION	8	Shows CDATASection nodes.
NodeFilter.SHOW_COMMENT	128	Shows Comment nodes.
NodeFilter.SHOW_DOCUMENT	256	Shows Document nodes.
NodeFilter.SHOW_DOCUMENT_FRAGMENT	1024	Shows DocumentFragment nodes.
NodeFilter.SHOW_DOCUMENT_TYPE	512	Shows DocumentType nodes.
NodeFilter.SHOW_ELEMENT	1	Shows Element nodes.
NodeFilter.SHOW_ENTITY	32	Shows Entity nodes. This is meaningful only when creating a TreeWalker with an Entity node as its root; in this case, it means that the Entity node will appear in the first position of the traversal. Since entities are not part of the document tree, they do not appear when traversing over the document tree.
NodeFilter.SHOW_ENTITY_REFERENCE	16	Shows EntityReference nodes.
NodeFilter.SHOW_NOTATION	2048	Shows Notation nodes. This is meaningful only when creating a TreeWalker with a Notation node as its root; in this case, it means that the Notation node will appear in the first position of the traversal. Since entities are not part of the document tree, they do not appear when traversing over the document tree.
NodeFilter.SHOW_PROCESSING_INSTRUCTION	64	Shows ProcessingInstruction nodes.
NodeFilter.SHOW_TEXT	4	Shows Text nodes.

filter Optional

An object implementing the NodeFilter interface. Its acceptNode() method will be called for each node in the subtree based at root which is accepted as included by the whatToShow flag to determine whether or not to include it in the list of iterable nodes (a simple callback function may also be used instead). The method should return one of NodeFilter.FILTER_ACCEPT, NodeFilter.FILTER_REJECT, or NodeFilter.FILTER_SKIP. See the Example.

Example

const nodeIterator = document.createNodeIterator(
    document.body,
    NodeFilter.SHOW_ELEMENT,
    {
      acceptNode(node) {
        return node.nodeName.toLowerCase() === 'p' ? NodeFilter.FILTER_ACCEPT : NodeFilter.FILTER_REJECT;
      }
    }
);
const pars = [];
let currentNode;

while (currentNode = nodeIterator.nextNode()) {
  pars.push(currentNode);
}

Specifications

Browser compatibility

BCD tables only load in the browser