<html>
<head>
<script type="text/javascript">
function isKeyPressed(event)
{
if (event.shiftKey==1)
alert("The shift key was pressed!")
}
else
alert("The shift key was NOT pressed!")
</script>
</head>
<body onmousedown="isKeyPressed(event)">
<p>在文档中点击某个位置。消息框会告诉你是否按下了 shift 键。</p>
</body>
</html>