<script src="https://cdn.staticfile.org/jquery/2.2.4/jquery.min.js"></script>

<label for="email">请输入一个邮箱: </label>

<input id="email" />

<h2 id="result"></h2>

const validateEmail = (email) => {

  return email.match(

    /^(([^<>()[\]\\.,;:\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,}))$/

  );

};

​

const validate = () => {

  const $result = $('#result');

  const email = $('#email').val();

  $result.text('');

​

  if (validateEmail(email)) {

    $result.text(email + ' 是一个正确的邮箱地址 :)');

    $result.css('color', 'green');

  } else {

    $result.text(email + ' 不是一个邮箱地址 :(');

    $result.css('color', 'red');

  }

  return false;

}

​

$('#email').on('input', validate);