<html>
<head>
<script type="text/javascript">
function writeMessage()
{
document.forms[0].mySecondInput.value=document.forms[0].myInput.value
}
</script>
</head>
<body>
<p>当键盘按键被按下时，会发生 onkeydown 事件。</p>
<form>
请输入您的名字：
<input type="text" name="myInput" onkeydown="writeMessage()" size="20">
<input type="text" name="mySecondInput" size="20">
</select>
</form>
</body>
</html>