​x
 
<!DOCTYPE html>
<html>
<head>
<style>
table, td {
  border: 1px solid black;
}
</style>
</head>
<body>
​
<p>单击按钮为表格创建标题元素。</p>
​
<table id="myTable">
  <tr>
    <td>单元格 1</td>
    <td>单元格 2</td>
  </tr>
  <tr>
    <td>单元格 3</td>
    <td>单元格 4</td>
  </tr>
</table>
<br> 
​
<button onclick="myFunction()">试一试</button>
​
<script>
function myFunction() {
  var table = document.getElementById("myTable").createCaption();
  table.innerHTML = "<b>我的表格标题</b>";
}
</script>
​
</body>
</html>
​