<html>
<head>
<script>
function displayResult()
{
var x;
if(window.event) // IE8 及更早IE版本
{
x=event.keyCode;
}
else if(event.which) // IE9/Firefox/Chrome/Opera/Safari
{
x=event.which;
}
keychar=String.fromCharCode(x);
alert("按键 " + keychar + " 被按下");
}
</script>
</head>
<body>
<p>当用户在输入域按下按键时触发函数。 该功能提醒按下的键。</p>
<input type="text" onkeypress="displayResult()">
</body>
</html>