JS如何判断PC或者移动端

<script type="text/javascript">
var userAgentInfo = navigator.userAgent;
var Agents = ["Android", "iPhone",
"SymbianOS", "Windows Phone",
"iPad", "iPod"];
var flag = false;
for (var v = 0; v < Agents.length; v++) {
if (userAgentInfo.indexOf(Agents[v]) > 0) {
flag = true;
break;
}
}

if(!flag){
window.location.href="./index.html";
}
</script>

<script type="text/javascript">
var userAgentInfo = navigator.userAgent;
var Agents = ["Android", "iPhone",
"SymbianOS", "Windows Phone",
"iPad", "iPod"];
var flag = false;
for (var v = 0; v < Agents.length; v++) {
if (userAgentInfo.indexOf(Agents[v]) > 0) {
flag = true;
break;
}
}

if(!flag){
window.location.href="./index.html";
}
</script>