判断PC或mobile设备

js 限制：

 <script type="text/javascript">
 function uaredirect(f){try{if(document.getElementById("bdmark")!=null){return}var b=false;if(arguments[1]){var e=window.location.host;var a=window.location.href;if(isSubdomain(arguments[1],e)==1){f=f+"/#m/"+a;b=true}else{if(isSubdomain(arguments[1],e)==2){f=f+"/#m/"+a;b=true}else{f=a;b=false}}}else{b=true}if(b){var c=window.location.hash;if(!c.match("pc")){if((navigator.userAgent.match(/(iPhoneiPodAndroidios)/i))){location.replace(f)}}}}catch(d){}}function isSubdomain(c,d){this.getdomain=function(f){var e=f.indexOf("://");if(e>0){var h=f.substr(e+3)}else{var h=f}var g=/^www\./;if(g.test(h)){h=h.substr(4)}return h};if(c==d){return 1}else{var c=this.getdomain(c);var b=this.getdomain(d);if(c==b){return 1}else{c=c.replace(".","\\.");var a=new RegExp("\\."+c+"$");if(b.match(a)){return 2}else{return 0}}}};
 uaredirect("http://www.test.com/mobile"); 

 </script>

php限制：

<?php

namespace app\controllers;

use yii\web\Controller;
use Yii;

class CommonController extends Controller
{
    public function init()
    {
        if (!empty($_COOKIE['lang'])) {
            $lang = $_COOKIE['lang'];
        } else {
            $lang = 'en';
        }
        if ($lang == 'cn') {
            Yii::$app->language = 'cn';
        } else {
            Yii::$app->language = 'en';
        }
        $tmp = self::isMobile();
        if ($tmp) {
            return $this->redirect('./index.php?r=mobile/home/index');
        } else {

        }
    }

    private function isMobile()
    {
        // 如果有HTTP_X_WAP_PROFILE则一定是移动设备
        if (isset($_SERVER['HTTP_X_WAP_PROFILE'])) {
            return TRUE;
        }
        // 如果via信息含有wap则一定是移动设备,部分服务商会屏蔽该信息
        if (isset($_SERVER['HTTP_VIA'])) {
            return stristr($_SERVER['HTTP_VIA'], "wap") ? TRUE : FALSE;
            // 找不到为flase,否则为TRUE
        }
        // 判断手机发送的客户端标志,兼容性有待提高
        if (isset($_SERVER['HTTP_USER_AGENT'])) {
            $clientkeywords = array('mobile', 'nokia', 'sony', 'ericsson', 'mot', 'samsung', 'htc', 'sgh', 'lg', 'sharp', 'sie-', 'philips', 'panasonic', 'alcatel', 'lenovo', 'iphone', 'ipod', 'blackberry', 'meizu', 'android', 'netfront', 'symbian', 'ucweb', 'windowsce', 'palm', 'operamini', 'operamobi', 'openwave', 'nexusone', 'cldc', 'midp', 'wap');
            // 从HTTP_USER_AGENT中查找手机浏览器的关键字
            if (preg_match("/(" . implode('', $clientkeywords) . ")/i", strtolower($_SERVER['HTTP_USER_AGENT']))) {
                return TRUE;
            }
        }
        if (isset($_SERVER['HTTP_ACCEPT'])) {
            // 协议法，因为有可能不准确，放到最后判断
            // 如果只支持wml并且不支持html那一定是移动设备
            // 如果支持wml和html但是wml在html之前则是移动设备
            if (strpos($_SERVER['HTTP_ACCEPT'], 'vnd.wap.wml') !== FALSE && (strpos($_SERVER['HTTP_ACCEPT'], 'text/html') === FALSE  strpos($_SERVER['HTTP_ACCEPT'], 'vnd.wap.wml') < strpos($_SERVER['HTTP_ACCEPT'], 'text/html'))) {
                return TRUE;
            }
        }
        return FALSE;
    }

}