在线运行代码 - 菜鸟教程

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(cainiaoplay.com)</title>
</head>
<body>

<form action="demo_keygen.php.html" method="get">
用户名: <input type="text" name="usr_name">
加密: <keygen id="myKeygen" name="security" autofocus>
<input type="submit">
</form>

<p>点击 "点我" 按钮查看 keygen 字段在页面载入后是否自动获取焦点。</p>
<p id="demo"></p>
<button onclick="myFunction()">点我</button>
<script>
function myFunction(){
	var x = document.getElementById("myKeygen").autofocus;
	document.getElementById("demo").innerHTML=x;
}
</script>

</body>
</html>
源代码

动行结果
