//JS根据访问终端对应显示【iPhone|iPad|iPod|iOS】、【Android】、【PC】三种不同的内容
//主要原理为：JS根据id值修改对应HTML标签属性
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8" />
<meta name="OS" content="width=device-width, initial-scale=1, maximum-scale=1">
<title></title>
<style type="text/css">
*{padding:0px;margin:0px;overflow:hidden;}
body{background:#fff;}
.adbox{calc(100% - 5px);margin-left:5px;height:auto;overflow:hidden;padding-bottom:5px;}
.adbox a{float:left;48%;-webkit-calc(100% / 2 - 5px);-moz-calc(100% / 2 - 5px);margin-right:5px;margin-top:5px;background:#f00;position:relative;}
.adbox a img{display:block;100%;}
.adbox a
</style>
</head>
<body>
<div class="adbox" id="adbox">
<div class="con">
<a id ="os_left"href='' target='_blank'><font color=black>点我吧←</font>
<img src="1.jpg" alt="" />
</a>
<a id ="os_right"href='' target='_blank'><font color=black>→点我呀</font>
<img src="2.jpg" alt="" />
</a>
</div>
</div>
<script type="text/javascript">
if(/(iPhone|iPad|iPod|iOS)/i.test(navigator.userAgent)){
document.getElementById("os_left").href="apple";
document.getElementById("os_right").hre ="apple";
} else if (/(Android)/i.test(navigator.userAgent)) {
document.getElementById("os_left").href="android";
document.getElementById("os_right").href="android";
} else {
document.getElementById("os_left").href="baidu";
document.getElementById("os_right").href="baidu";
}
</script>
</body>
</html>
文章来源：微笔记_博客