HTML DOM childNodes 属性

<p id="demo">单击“按钮”获取有关身体元素的子节点的信息</p>
<button onclick="myFunction()">点我</button>
<script>
  function myFunction() {
    var txt = "";
    var c = document.body.childNodes;
    for (i = 0; i < c.length; i++) {
      txt = txt + c[i].nodeName + "<br>";
    };
    var x = document.getElementById("demo");
    x.innerHTML = txt;
  }
</script>
<p><strong>注意:</strong> 空格内元素看作是文本，文本是节点。</p>