<html>
<head>
<script type="text/javascript">
function aboveFrames()
{
document.getElementById('myTable').frame="above"
}
function belowFrames()
document.getElementById('myTable').frame="below"
</script>
</head>
<body>
<table id="myTable">
<tr>
<td>100</td>
<td>200</td>
</tr>
<td>300</td>
<td>400</td>
</table>
<br />
<input type="button" onclick="aboveFrames()" value="显示上边框">
<input type="button" onclick="belowFrames()" value="显示下边框">
</body>
</html>