合并一相同节点 - 在线编辑器

          <p id="demo">单击按钮添加文本，单击另一个按钮标准化元素。</p>
<button onclick="addTextNode()">添加一个文本节点</button>
<button onclick="normPara()">规格化段落</button>
<script>
  function addTextNode() {
    var y = document.createTextNode(" Click again");
    var x = document.getElementById("demo");
    x.appendChild(y);
    var z = document.getElementById("cc");
    z.innerHTML = x.childNodes.length;
  }

  function normPara() {
    var x = document.getElementById("demo");
    x.normalize();
    var z = document.getElementById("cc");
    z.innerHTML = x.childNodes.length;
  }
</script>
<p>上面的段落有 <span id="cc">1</span>子节点。</p>
        