下面的例子在表格行中插入了一个单元 - 在线编辑器

          <!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>蜜蜂教程(mifengjc.com)</title>
  <script>
    function displayResult() {
      var firstRow = document.getElementById("myTable").rows[0];
      var x = firstRow.insertCell(-1);
      x.innerHTML = "New cell"
    }
  </script>
</head>
<body>

  <table id="myTable" border="1">
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
    </tr>
  </table>
  <br>
  <button type="button" onclick="displayResult()">插入单元格</button>

</body>
</html>
        