Firebase example

index.html

<div id="currentNumber"> </div>

<button id="increment">+</button>
<button id="reset">Reset</button>

<script src="https://cdn.firebase.com/v0/firebase.js"></script>
<script>
    var currentNumber = document.getElementById('currentNumber');
    var incrementButton = document.getElementById('increment');
    var resetButton = document.getElementById('reset');

    var number = new Firebase("https://iuav-ixdlab-bottles.firebaseio.com/number");

    number.on('value', function(snapshot) {
        currentNumber.innerHTML = snapshot.val();
    });

    incrementButton.addEventListener('touchstart', function() {
        number.transaction(function(current_value) {
            return current_value + 1;
        });
    });

    resetButton.addEventListener('touchstart', function() {
        number.set(0);
    });

</script>