sendMessage.html

<div id="questionsContainer">
  <label for="question">Qual sua pergunta, <span id="userName"></span>?</label>
  <input id="question" onfocus="clearMessage()" onKeyUp="checkEnter(event)"></input>
  <p id="feedBack"></p>
  <button id="sendButton" onClick="sendMessage()">Enviar</button>
</div>

sendMessage.js

function checkEnter (event) {
  if (event.key === "Enter") {
    sendMessage()
  }
}
function clearMessage () {
  feedBack.innerHTML = ''
  feedBack.className = ''
}
function sendMessage () {
  idleButton()
  newMessageRef = databaseRef.push()
  var displayName = userAuthData.user.displayName
  var email = userAuthData.user.email
  newMessageRef.set({question, createdAt, displayName, email}, (err) => {
    sending = false
    if (!err) {
      setSuccessFeedback('Pergunta enviada!')
    } else {
      setError('Algo deu errado, tente novamente mais tarde ;)')
    }
  })
}