NodeFilter

A NodeFilter interface represents an object used to filter the nodes in a NodeIterator or TreeWalker . A NodeFilter knows nothing about the document or traversing nodes; it only knows how to evaluate a single node against the provided filter.

注意: The browser doesn't provide any object implementing this interface. It is the user who is expected to write one, tailoring the acceptNode() method to its needs, and using it with some TreeWalker or NodeIterator 对象。

特性

This interface neither implements nor inherits any properties.

方法

This interface doesn't inherit any methods.

NodeFilter.acceptNode()

Returns an unsigned short that will be used to tell if a given Node must be accepted or not by the NodeIterator or TreeWalker iteration algorithm.

This method is expected to be written by the user of a NodeFilter . Possible return values are:

常量 描述
FILTER_ACCEPT Value returned by the NodeFilter.acceptNode() method when a node should be accepted.
FILTER_REJECT

Value to be returned by the NodeFilter.acceptNode() method when a node should be rejected. For TreeWalker , child nodes are also rejected.

For NodeIterator , this flag is synonymous with FILTER_SKIP .

FILTER_SKIP

Value to be returned by NodeFilter.acceptNode() for nodes to be skipped by the NodeIterator or TreeWalker 对象。

The children of skipped nodes are still considered. This is treated as "skip this node but not its children".

范例

const nodeIterator = document.createNodeIterator(
  // Node to use as root
  document.getElementById('someId'),
  // Only consider nodes that are text nodes (nodeType 3)
  NodeFilter.SHOW_TEXT,
  // Object containing the function to use for the acceptNode method
  // of the NodeFilter
  {
    acceptNode: function(node) {
      // Logic to determine whether to accept, reject or skip node
      // In this case, only accept nodes that have content
      // other than whitespace
      if (/\S/.test(node.data)) {
        return NodeFilter.FILTER_ACCEPT
      }
    }
  },
  false
);
// Show the content of every non-empty text node that is a child of root
let node;
while ((node = nodeIterator.nextNode())) {
  alert(node.data)
}
					

规范

规范 状态 Comment
DOM
The definition of 'NodeFilter' in that specification.
实时标准
Document Object Model (DOM) Level 2 Traversal and Range Specification
The definition of 'NodeFilter' in that specification.
Obsolete 初始定义。

浏览器兼容性

更新 GitHub 上的兼容性数据
Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
NodeFilter Chrome 1 Edge 12 Firefox 2 IE 9 Opera 9 Safari 3 WebView Android Yes Chrome Android Yes Firefox Android 4 Opera Android 10.1 Safari iOS 3 Samsung Internet Android Yes
acceptNode Chrome 1 Edge 12 Firefox 2 IE 9 Opera 9 Safari 3 WebView Android Yes Chrome Android Yes Firefox Android 4 Opera Android 10.1 Safari iOS 3 Samsung Internet Android Yes

图例

完整支持
完整支持

另请参阅