script.js

var config = {
  apiKey: "AIzaSyAj1Z6YANlX8Odun_s-_MSN6CwxPakMfSU",
  authDomain: "sign-in-sample-fe5af.firebaseapp.com",
  databaseURL: "https://sign-in-sample-fe5af.firebaseio.com",
  projectId: "sign-in-sample-fe5af",
  storageBucket: "sign-in-sample-fe5af.appspot.com",
  messagingSenderId: "1006039985068"
};
firebase.initializeApp(config);

function toggleSignIn() {
  if (firebase.auth().currentUser) {
    // [START signout]
    firebase.auth().signOut();
    // [END signout]
  } else {
    var email = document.getElementById("email").value;
    var password = document.getElementById("password").value;
    if (email.length < 4) {
      alert("Please enter an email address.");
      return;
    }
    if (password.length < 4) {
      alert("Please enter a password.");
      return;
    }
    // Sign in with email and pass.
    // [START authwithemail]
    firebase
      .auth()
      .signInWithEmailAndPassword(email, password)
      .catch(function(error) {
        // Handle Errors here.
        var errorCode = error.code;
        var errorMessage = error.message;
        // [START_EXCLUDE]
        if (errorCode === "auth/wrong-password") {
          alert("Wrong password.");
        } else {
          alert(errorMessage);
        }
        console.log(error);
        document.getElementById("quickstart-sign-in").disabled = false;
        // [END_EXCLUDE]
      });
    // [END authwithemail]
  }
  document.getElementById("quickstart-sign-in").disabled = true;
}
/**
 * Handles the sign up button press.
 */
function handleSignUp() {
  var email = document.getElementById("email").value;
  var password = document.getElementById("password").value;
  if (email.length < 4) {
    alert("Please enter an email address.");
    return;
  }
  if (password.length < 4) {
    alert("Please enter a password.");
    return;
  }
  // Sign in with email and pass.
  // [START createwithemail]
  firebase
    .auth()
    .createUserWithEmailAndPassword(email, password)
    .catch(function(error) {
      // Handle Errors here.
      var errorCode = error.code;
      var errorMessage = error.message;
      // [START_EXCLUDE]
      if (errorCode == "auth/weak-password") {
        alert("The password is too weak.");
      } else {
        alert(errorMessage);
      }
      console.log(error);
      // [END_EXCLUDE]
    });
  // [END createwithemail]
}

/**
 * initApp handles setting up UI event listeners and registering Firebase auth listeners:
 *  - firebase.auth().onAuthStateChanged: This listener is called when the user is signed in or
 *    out, and that is where we update the UI.
 */
function initApp() {
  // Listening for auth state changes.
  // [START authstatelistener]
  firebase.auth().onAuthStateChanged(function(user) {
    if (user) {
      // User is signed in.
      var displayName = user.displayName;
      var email = user.email;
      var emailVerified = user.emailVerified;
      var photoURL = user.photoURL;
      var isAnonymous = user.isAnonymous;
      var uid = user.uid;
      var providerData = user.providerData;

      document.getElementById("quickstart-sign-in").textContent = "Sign out";

      if (!emailVerified) {
        document.getElementById("quickstart-verify-email").disabled = false;
      }
    } else {
      document.getElementById("quickstart-sign-in").textContent = "Sign in";
    }

    document.getElementById("quickstart-sign-in").disabled = false;
  });
  // [END authstatelistener]
  document
    .getElementById("quickstart-sign-in")
    .addEventListener("click", toggleSignIn, false);
  document
    .getElementById("quickstart-sign-up")
    .addEventListener("click", handleSignUp, false);
}
window.onload = function() {
  initApp();
};