form-valid.js

const inputList = Array.prototype.slice.call(document.getElementsByTagName('input')).filter(item => item.type !== 'submit' && item.type !== 'checkbox');
const input = inputList.concat(Array.prototype.slice.call(document.getElementsByTagName('textarea')));

//valid each item and set error message
  function isValid(input) {
    const target = input.id ? input.id : input.target.id;
    const valid = document.getElementById(target).validity.valid;
    if (valid) {
      document.getElementById(`${target}-error`).classList.remove('invalid');
      document.getElementById(`${target}-error`).removeAttribute('role');
      document.getElementById(target).setAttribute('aria-invalid', 'false');
    } else {
      document.getElementById(`${target}-error`).classList.add('invalid');
      document.getElementById(`${target}-error`).setAttribute('role', 'alert');
      document.getElementById(target).setAttribute('aria-invalid', 'true');
      console.log(document.getElementById(target));
    }

    if (document.getElementById('form-message').value.length !== length) {
      length = document.getElementById('form-message').value.length;
      document.getElementById('form-message-length').innerText = length;
    }

    return valid;
  }