PHP:获取客户端MAC地址

<script type="text/javascript">
    function getMacAddress() {
        var macAddress = "";
        var obj = new ActiveXObject("WbemScripting.SWbemLocator");
        var service = obj.ConnectServer(".");
        var properties = service.ExecQuery("SELECT * FROM Win32_NetworkAdapterConfiguration");
        var e = new Enumerator(properties);
        for (; !e.atEnd(); e.moveNext()) {
            var p = e.item();
            if (p.MACAddress != null) {
                macAddress = p.MACAddress;
                break;
            }
        }
        return macAddress;
    }
</script>

<?php
function getMacAddress($ip) {
    $output = shell_exec("arp -a " . $ip);
    $regex = '/([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})/';
    preg_match($regex, $output, $matches);
    if (isset($matches[0])) {
        return $matches[0];
    } else {
        return "MAC地址未找到";
    }
}

$ip = $_SERVER['REMOTE_ADDR'];
$macAddress = getMacAddress($ip);
echo "客户端IP地址：" . $ip . "<br>";
echo "客户端MAC地址：" . $macAddress;
?>