index.html

<!DOCTYPE HTML>
<html>

<head>
    <meta charset="UTF-8">
    <title>Main</title>
    <style>
        html,
        head,
        body {
            padding: 0;
            margin: 0;
        }

        body {
            font-family: calibri, helvetica, arial, sans-serif;
        }
    </style>
    <script src="js/ion.sound.min.js"></script>
    <script src="Main.js"></script>
</head>

<body>
    <script type="text/javascript">
        var app = Elm.Main.fullscreen()

        ion.sound({
            sounds: [{
                name: "bell_ring"
            }],
            volume: 1.0,
            path: "sounds/",
            preload: true,
            ended_callback: function(obj) {
                app.ports.soundEnded.send("Finished");
            }
        });

        app.ports.playSound.subscribe(function(sound) {
            ion.sound.play(sound);
        });
    </script>
</body>

</html>