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;

    //此条摘自TPM智能切换模板引擎，适合TPM开发

    if(isset ($_SERVER['HTTP_CLIENT'])

        &&'PhoneClient'==$_SERVER['HTTP_CLIENT'])

        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']))

        //找不到为flase,否则为true

        return stristr($_SERVER['HTTP_VIA'],

            'wap') ? true : false;

    //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(

            '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','mobile'

        );

        //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;

        }

    }

    //协议法，因为有可能不准确，放到最后判断

    if (isset ($_SERVER['HTTP_ACCEPT'])) {

        // 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;

}

//判断是pc端还是手机端

        if(isMobile()){

            C('DEFAULT_V_LAYER','Mobile');

        }