为什么手机端要加这几条代码啊,,,求大神,让我长知识

Question

<meta name="viewport" content="width=device-width,initial-scale=1.0,maximum-scale=1.0,minimum-scale=1.0,user-scalable=no">
<meta name="format-detection" content="telephone=no" />
<meta name="apple-mobile-web-app-capable" content="yes" />
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<meta http-equiv="pragma" content="no-cache" />

求大神..........