Check if you can access Firebase data with anonymous auth

first.js

var fbScripTag = document.createElement('script');
fbScripTag.setAttribute('src','https://www.gstatic.com/firebasejs/4.8.1/firebase.js');
document.head.appendChild(fbScripTag);

second.js

var config = {
    apiKey: "<API_KEY>",
    authDomain: "<PROJECT_ID>.firebaseapp.com",
    databaseURL: "https://<DATABASE_NAME>.firebaseio.com",
    storageBucket: "<BUCKET>.appspot.com",
    messagingSenderId: "<SENDER_ID>",
  };
firebase.initializeApp(config);
firebase.auth().signInAnonymously().catch(function(error) {console.log(error)})
var database = firebase.database();
database.ref("/").once("value").then(function(stuff) {console.log(stuff.val())});