feedBack.html

<p id="feedBack"></p>

feedbackColors.css

#feedBack {
  margin: 0;
  margin-bottom: 1em;
}
.hasError  {
  color: #E75854;
}
.hasSuccess {
  color: #3BB86C;
}

handleMessage.js

function clearMessage () {
    feedBack.innerHTML = ''
    feedBack.className = ''
  }
  function setError (message) {
    enableButton()
    var feedBack = document.getElementById('feedBack')
    feedBack.innerHTML = message
    feedBack.className = 'hasError'
  }
  function setSuccessFeedback (message) {
    enableButton()
    var feedBack = document.getElementById('feedBack')
    feedBack.innerHTML = message
    feedBack.className = 'hasSuccess'
  }