app4.js

(function (){
	document.getElementById('eventClick').onclick= function(){	
		document.getElementById('ClickMe').innerHTML++; 
		}

	const config = {
		 apiKey: "AIzaSyByiVZCx2lMwJerAGR6TkgLXhozKvEwrO8",
	    authDomain: "silent-relic-219002.firebaseapp.com",
    	databaseURL: "https://silent-relic-219002.firebaseio.com",
    	projectId: "silent-relic-219002",
   		storageBucket: "silent-relic-219002.appspot.com",
    	messagingSenderId: "515739637546"
  		};
  		firebase.initializeApp(config);


	//Auth listener
    firebase.auth().onAuthStateChanged(firebaseUser => {
        console.log(firebaseUser);
        if(firebaseUser){
            alert("Congratulations! You are logged in!");			
						}
		else{
			document.getElementById('eventClick').style.display = 'none';
			alert("You are not logged in! Access denied!");
        }
    });
	
 }());