title: Allow + in regex email validate email
body: <p>Regex is blowing my mind. How can I change this to validate emails with a plus sign? so I can sign up with test+spam@gmail.com</p>
  
  <pre><code>if(!preg_match("/^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*$/i", $_GET['em'])) {
  </code></pre>