Document.createNodeIterator()

const nodeIterator = document.createNodeIterator(root[, whatToShow[, filter]]); 
语法: 遍历起始处的根节点

显示所有节点： NodeFilter.SHOW_ALL

显示文本节点： NodeFilter.SHOW_TEXT

实例：

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);
}