<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><tr><td>300</td><td>400</td></tr></table><br /><input type="button" οnclick="aboveFrames()" value="显示上边框"><input type="button" οnclick="belowFrames()" value="显示下边框">
</body></html>