<!DOCTYPE html>

<head>
    <title>Test network status</title>
</head>

<body style="color: white;">
    <h1>
        <span>Network Status Value:</span>
        <span id="net_stat">n/a</span>
    </h1>

    <script>
        window.addEventListener('offline', function (e) {
            console.log('offline');
            document.getElementById('net_stat').innerHTML = "False";
        });
        window.addEventListener('online', function (e) {
            console.log('online');
            document.getElementById('net_stat').innerHTML = "True";
        });
    </script>
</body>