<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <script type="text/javascript">
            function permission_cb(permission) {
                switch (permission) {
                    case "granted":
                        console.log("notification permission granted");
                        break;
                    case "denied":
                        console.log("notification permission denied");
                        break;
                    case "default":
                        console.log("notification permission aborted");
                        break;
                    default:
                        console.log("[FAIL] unknown value for permission: " + Notification.permission);
                        break;
                }
            }

            function get_notification_permission() {
                if ("Notification" in window) {
                    if (Notification.permission === "default") {
                        Notification.requestPermission(permission_cb);
                    } else {
                        console.log("[FAIL] unknown initial value for Notification.permission: " + Notification.permission);
                    }
                } else {
                    console.log("[FAIL] notifications unavailable");
                }
            }
        </script>
    </head>
    <body>
        <input type="button" onclick="get_notification_permission()" value="Get notification permission" id="button">
    </body>
</html>