Firebase test:
<br><br><br>

testvalueJSON----------------------------
<br>
<span id = "message">
Loading.............
</span>

<br><br><br>
entireJSON----------------------------
<br>
<span id = "entireJSON">
  Loading.............
</span>

<script src="https://www.gstatic.com/firebasejs/4.8.1/firebase.js"></script>
<script>

function updateElement(id, message){
  var ele = document.getElementById(id);
  ele.innerHTML = message;
}

  var config = {
    apiKey: "AIzaSyCguA9cODISEwGYYh80I1Edmkf41ySlMWY",
    authDomain: "testlevel3-c904f.firebaseapp.com",
    databaseURL: "https://testlevel3-c904f.firebaseio.com",
    projectId: "testlevel3-c904f",
    storageBucket: "testlevel3-c904f.appspot.com",
    messagingSenderId: "387009646612"
  };
  firebase.initializeApp(config);
  var data = firebase.database().ref().child("allProducts");
  data.once('value',function(snapshot){
    var jsonStr = JSON.stringify(snapshot.val());
    var json = JSON.parse(jsonStr);

    updateElement("message",json.productList[0].productId);

    updateElement("entireJSON",jsonStr);


    //alert("firebase value recorded");
  });


</script>