title: Email entry regex validation
body: <p>I am using the following regex to validate an email address:</p>
  
  <pre><code>"^[-a-zA-Z0-9][-.a-zA-Z0-9]*@[-.a-zA-Z0-9]+(\.[-.a-zA-Z0-9]+)*\.(com|edu|info|gov|int|mil|net|org|biz|name|museum|coop|aero|pro|[a-zA-Z]{2})$"
  </code></pre>
  
  <p>Unfortunately, this does not allow email addresses with <strike>hyphens</strike> underscores. Ex.: </p>
  
  <blockquote>
    <p>first_last@abc.com</p>
  </blockquote>
  
  <p>How can I modify this to allow <strike>hyphens</strike> underscores?</p>