问Javascript - firebase.auth().onAuthStateChanged在登录/注销时不触发

EN

var config = {
       apiKey: "xxxxx",
       authDomain: "xxxxx",
       databaseURL: "xxxxx",
       projectId: "xxxxx",
       storageBucket: "xxxxx",
       messagingSenderId: "xxxxx"
};

firebase.initializeApp(config);

$("#loginButton").on('click', function(){
    logIn($("#email").val(), $("#pwd").val());
});

$("#logoutButton").on('click', function(){
   firebase.auth().signOut();
   console.log("clicked logout button");
});

function logIn(email, password){
   firebase.auth().signInWithEmailAndPassword(email,    password).catch(function(error) {
    // Handle Errors here.
    var errorCode = error.code;
    var errorMessage = error.message;
    alert(error.message);
  });
}

firebase.auth().onAuthStateChanged(function(user) {
    if (user) {
      console.log("Signed in");                  
      firebase.auth().currentUser.getIdToken(true).then(function(idToken) {
        // Send token to your backend via HTTPS
        // ...
        console.log("Token = " + idToken);
        console.log("Logged in!");
        $("#loginButton").val(idToken);
        $("#loginForm").submit();
      }).catch(function(error) {
           // Handle error
           console.log(error);
      });
   }
   else{
       console.log("User signed out");
   }
});