显示第一行的单元格数量 - 在线编辑器

          <!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>蜜蜂教程(mifengjc.com)</title>
  <script>
    function displayResult() {
      alert(document.getElementById("myTable").rows[0].cells.length);
    }
  </script>
</head>
<body>

  <table id="myTable" border="1">
    <tr>
      <td>cell 1</td>
      <td>cell 2</td>
    </tr>
    <tr>
      <td>cell 3</td>
      <td>cell 4</td>
    </tr>
  </table>
  <br>
  <button type="button" onclick="displayResult()">显示第一行单元格的数量</button>

</body>
</html>
        