使用提取标签方法 ,返回NodeList=> 转为数组 => 使用map获取tagName =>Set去重
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<h1></h1>
<h1></h1>
<h1></h1>
<h1></h1>
<script>
// 1. 找到所有的html标签
var html = [...document.querySelectorAll("*")]
// console.log(document.querySelectorAll("*"));
console.log(html);
// 2. 提取html标签名
var tagName = html.map(v=>v.tagName)
console.log(tagName);
// 3. 去重
var res = [...new Set(tagName)]
console.log(res);
</script>
</body>
</html>
综合
[...new Set([...document.querySelectorAll("*")].map(v=>v.tagName))]
[...new Set(Array.prototype.slice.call(document.querySelectorAll("*")).map(v=>v.tagName))]
