Tryit Editor v2.9

Edit This Code:
<!DOCTYPE html>
<html>
<head>
<style>
table, th, td {
    border: 1px solid black;
}
</style>
</head>
<body>

<p>Click the button to change the value of the rowspan attribute, from 2 to 1, of th with id "myTh".</p>

<table>
  <tr>
    <th id="myTh" rowspan="2">Month</th>
    <th>Savings</th>
  </tr>
  <tr>
    <td>January</td>
    <td>$100</td>
  </tr>
  <tr>
    <td>February</td>
    <td>$100</td>
  </tr>
</table>
<br> 

<button onclick="myFunction()">Try it</button>

<script>
function myFunction() {
    document.getElementById("myTh").rowSpan = "1";
}
</script>

</body>
</html>