<html>
<head>
<script type="text/javascript">
function whichButton(event)
{
alert(event.keyCode)
}
</script>
</head>
<body onkeyup="whichButton(event)">
<p><b>注释：</b>在测试这个例子时，要确保右侧的框架获得了焦点。</p>
<p>在键盘上按一个键。消息框会提示出该按键的 unicode。</p>
</body>
</html>