\n\t\tsubmit.className = isValid ? \&quot;submit\&quot; : \&quot;disabled\&quot;;\n    \n    return isValid;\n  &#125;\n\n  function emailErrorMessage(input, allDivs) &#123;\n    input.className = \&quot;required invalid\&quot;;\n    input.placeholder = input.getAttribute(\&quot;data-required-message\&quot;) &#124;&#124; \&quot;This field is required\&quot;;\n  &#125;\n\n  function fieldErrorMessage(input, allDivs) &#123;\n    input.className = \&quot;required invalid\&quot;;\n    input.placeholder = input.