Answers for "allow only one email address javascript validation"

regex pattern to validate email

[a-zA-Z0-9._-]{3,}@[a-zA-Z0-9.-]{3,}.[a-zA-Z]{2,4}

js validate email

function validateEmail(email) {
  var re = /^(([^<>()[]\.,;:s@"]+(.[^<>()[]\.,;:s@"]+)*)|(".+"))@(([[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}])|(([a-zA-Z-0-9]+.)+[a-zA-Z]{2,}))$/;
  return re.test(email);
}