忽略变量环境，引用全局变量
html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>globalThis</title>
</head>
<body>
<script>
console.log(globalThis);
</script>
</body>
</html>
js
console.log(globalThis);