firebase auth with email and password not working

Question

I wrote a webapp that has a login form but it does not work and it does not returns any error. Here the main.js function and the HTML code that calls that.

function signinUser() {
    var email = document.getElementById("inputEmail").value;
    var password = document.getElementById("inputPassword").value;

    firebase.auth().signInWithEmailAndPassword(email, password).then((userCredential) => {
        var user = userCredential.user;

        console.log(user);
    }).catch((error) => {
        var errorCode = error.code;
        var errorMessage = error.message;

        if (errorCode === 'auth/wrong-password')
            alert("Password errata!");

        console.log("Error code: " + errorCode);
        console.log("Error message: " + errorMessage);
    });
}

This is the HTML code on my login page:

<form id="login" class="form-signin position-absolute top-50 start-50 translate-middle">
    <img class="mb-4" src="img/logo.png" alt="" width="72" height="72">
    <h1 class="h3 mb-3 fw-normal">Login</h1>
    <label for="inputEmail" class="visually-hidden">Email address</label>
    <input type="email" id="inputEmail" class="form-control" placeholder="Email address" required autofocus>
    <label for="inputPassword" class="visually-hidden">Password</label>
    <input type="password" id="inputPassword" class="form-control" placeholder="Password" required>
    <div class="checkbox mb-3">
        <label>
            <input type="checkbox" value="remember-me"> Remember me
        </label>
    </div>
    <button class="w-100 btn btn-lg btn-primary" type="submit" onclick="signinUser();">Sign in</button>
    <p class="mt-5 mb-3 text-muted">&copy; 2021</p>
</form>

Answer 1

In your form you declare your button as a button of type submit :

<button class="w-100 btn btn-lg btn-primary" type="submit" onclick="signinUser();">Sign in</button>

This results in the fact that your form is submitted before the asynchronous Firebase signInWithEmailAndPassword() method is completed.

Changing the button to type="button" will solve the problem (See W3 specification ). The form will not be submitted but this is not a problem at all: you don't want the form to be submitted, you just want the Firebasse method to be called with the correct values taken from the form (ie email and password ).