meta

适用于`head`标签内

<meta name="author" content="Chris Mills">
<meta name="description" content="The MDN Learning Area aims to provide
complete beginners to the Web with all they need to know to get
started with developing web sites and applications.">

许多 <meta> 特性已经不再使用：

• 因为作弊者填充了大量关键词到keyword， 错误地引导搜索结果<meta name="keywords" content="fill, in, your, keywords, here"

还可以自定义：

• 如mdn的自定义协议：http://ogp.me/