Cómo verificar un usuario está utilizando datos WiFi o celulares en PHP

<html>
    <head>
        <script type="text/javascript">
            function checkWIFI() {
                var output = document.getElementById('connectionCheck');
                var html = "Checking...<br/>Connection: ";
                if (navigator.connection) {
                    var type = navigator.connection.type;
                    html += type
                } else {
                    html += "Connection type not supported.";
                }
                output.innerHTML = html;
            }
        </script>
    </head>
    <body onload="checkWIFI();">
        <div id="connectionCheck">
        </div>
    </body>
</html>
Enthusiastic Echidna