<html>
<head>
<title>我的标题</title>
</head>
<body>
<h1>Document 对象</h1>
<h2>head 属性</h2>
<p>head 属性的标签名称是:</p>
<p id="demo"></p>
<script>
let tag = document.head.tagName;
document.getElementById("demo").innerHTML = tag;
</script>
</body>
</html>