在线运行代码 - 代码学院 www.codexy.cn

<!DOCTYPE html>
<html>
<head> 
<meta charset="utf-8"> 
<title>代码学院(codexy.cn)</title> 
<script>
function displayResult(){
	document.getElementById("myHeader1").rowSpan="2";
}
</script>
</head>
<body>

<table border="1">
	<tr>
		<th id="myHeader1">Month</th>
		<th id="myHeader2">Savings</th>
	</tr>
  	<tr>
		<td>January</td>
		<td>$100.00</td>
  	</tr>
  	<tr>
		<td>February</td>
		<td>$10.00</td>
  	</tr>
  <tr>
    <td>March</td>
    <td>$80.00</td>
  </tr>
</table>
<br> 
<button type="button" onclick="displayResult()">修改第一个单元格横跨的行数</button>

</body>
</html>

源代码

动行结果