​x
 
<html>
<head>
<style type="text/css">
caption
{
caption-side:bottom; 
}
</style>
<script type="text/javascript">
function moveCaption()
{
document.getElementById('myTable').style.captionSide="right";
}
</script>
</head>
<body>
​
<table border="1" id="myTable">
  <caption>This is a caption</caption>
  <tr>
    <td>100</td>
    <td>200</td>
  </tr>
  <tr>
    <td>300</td>
    <td>400</td>
  </tr>
</table>
<br />
<input type="button" onclick="moveCaption()" value="Move table caption">
​
</body>
</html>
​