HTML utilizado na aula

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Trabalhando com Eventos</title>
  <script src="./index.js" defer></script>
</head>
<body>
  <h1>Trabalhando com Eventos no Javascript</h1>
  <hr>

  <h2>Registre-se!</h2>
  <section>
    <label for="username">Nome de Usuário:</label>
    <input type="text" name="username" id="username">
    <br>
    <label for="password">Senha:</label>
    <input type="password" name="password" id="password">
    <br>
    <label for="passwordConfirmation">Confirme sua senha:</label>
    <input type="password" name="passwordConfirmation" id="passwordConfirmation">
    <br>
    <button id="register-button">Registrar</button>
    <button onclick="removeEvent()">Remover Event Listener</button>
  </section>
</body>
</html>

Javascript utilizado na aula

function register(ev) {
  console.log(ev)
  const sectionElement = ev.currentTarget.parentNode
  const username = sectionElement.children.username.value
  const password = sectionElement.children.password.value
  const passwordConfirmation = sectionElement.children.passwordConfirmation.value

  if (password === passwordConfirmation) {
    alert("Usuário " + username + " registrado!")
  } else {
    alert("As senhas não conferem")
  }
}

function removeEvent() {
  button.removeEventListener("click", register)
  alert("Event Removed")
}

const button = document.getElementById("register-button")

button.addEventListener("click", register)

button.addEventListener("mouseover", function (ev) {
  console.log(ev)
})