// VALIDA EMAIL
emailRE = new RegExp("^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$");
function validaEmail() {
  var email = document.getElementById("email").value;
  if (emailRE.test(email)) {
    var formulario = document.getElementById("formulario");
    formulario.action = "contato.php";
    formulario.submit();
  }
  alert("ATENÇÃO \n\n E-mail inválido");
  return false;
}