js node 节点 原生遍历 createNodeIterator

return node.tagName.toLowerCase() == ‘p‘ ?
    NodeFilter.FILTER_ACCEPT:
    NodeFilter.FILTER_REJECT;
}


var iterator = document.createNodeIterator(root, NodeFilter.SHOW_ELEMENT, filter, false);

var node = iterator.nextNode();

while(node !== null){
    console.log( node.tagName ); 

    // node 的属性 与方法 详见 2 nodeFilter
    node = iterator.nextNode();
}


 ———————————————— 
基于此，可以简单的做为 web node 节点的数据 采集

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);
}

while(node !== null){
    console.log( node.tagName ); 
   //node.tagName  等于 element.tagName 
  // element 的属性 与方法 详见 3、

    node = iterator.nextNode();
}