<html>

<head>

<script type="text/javascript">

function whichButton(event)

{

var btnNum = event.button;

if (btnNum==2)

  {

  alert("您点击了鼠标左键!")

  }

else if(btnNum==0)

  {

  alert("您点击了鼠标右键!")

  }

else if(btnNum==1)

  {

  alert("您点击了鼠标中键!");

  }

else

  {

  alert("您点击了" + btnNum+ "号键,我不能确定它的名称。");

  }

}

</script>

</head>

<body onmousedown="whichButton(event)">

<p>请在文档中点击鼠标。一个消息框会提示出您点击了哪个鼠标按键。</p>

</body>

</html>