index.html

<script src='https://cdn.firebase.com/js/client/2.2.1/firebase.js'></script>
<script src='https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js'></script>
<script type="text/javascript">
    var db = new Firebase('https://chat-balta-demo.firebaseio.com/chat');
    $('#send-button').click(function () {
        var message = $('#text-message').val();
        db.push({ message: message });
        $('#text-message').val("");
    });

    db.on('child_added', function(snapshot) {
        var data = snapshot.val();
        $('#messages').append($('<li>').text(data.message));
    });
</script>