NodeFilter

NodeFilter 接口表示一个对象，此对象用于过滤 NodeIterator 或 TreeWalker 中的节点。它既不能处理 DOM，又不能遍历节点；它只能根据提供的过滤器对单个节点进行评估与判定。

属性

此接口没有实现或继承任何属性。

方法

此接口不继承任何方法。

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:

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

例子

var 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
var node;

while ((node = nodeIterator.nextNode())) {
  alert(node.data);
}

规范

浏览器兼容性

参见

• 相关接口：TreeWalker、NodeIterator。