function ltrim(s) {
  return s.replace(/^\s+/, "");
}
function rtrim(s) {
  return s.replace(/\s+$/, "");
}
function trim(s) {
  return rtrim(ltrim(s));
}
function validarMail(mail) {
  var filtro = /^[A-Za-z][A-Za-z0-9_.]*@[A-Za-z0-9_]+\.[A-Za-z0-9_.]+[A-za-z]$/;
  if (filtro.test(mail)) return true; return false;
}