JS代码：

<script>    
    var noRedirect = location.search.split('noRedirect=')[1]
    if ( ( noRedirect == null) || noRedirect.toString() != 'true' ){
        if( navigator.userAgent.match(/Android/i)
        || navigator.userAgent.match(/webOS/i)
        || navigator.userAgent.match(/iPhone/i)
        || navigator.userAgent.match(/iPad/i)
        || navigator.userAgent.match(/iPod/i)
        || navigator.userAgent.match(/BlackBerry/i)
        || navigator.userAgent.match(/Windows Phone/i)
          )
        {
            location.href = 'https://m.baidu.com/';
        }
    }
</script>

PHP代码：

    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'])) {
        // 找不到为flase,否则为true
        return stristr($_SERVER['HTTP_VIA'], "wap") ? true : false;
    }
    // 脑残法，判断手机发送的客户端标志,兼容性有待提高。其中'MicroMessenger'是电脑微信
    if (isset($_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','MicroMessenger');
        // 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;
}