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>

<script>
let site = ['cainiaoplay', 'google', 'taobao'];

document.write(site.includes('cainiaoplay'));
// true 

document.write("<br>"); 
	
document.write(site.includes('baidu')); 
// false
</script>

</body>
</html>

源代码

动行结果