<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title></title>
<form>
<input type="button" value="点击" onclick="message()">
</form>
</head>
<body>
<script type="text/javascript">
function message(event)
{
alert(event.type)
}
</script>
</body>
</html>
把message的参数event去掉就可以了，当然更好的写法是加一句event=event||window.event;