title: Regex for validating multiple E-Mail-Addresses
body: <p>I got a Regex that validates my mail-addresses like this:</p>
  
  <p><code>([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)</code></p>
  
  <p>This works perfectly fine, but only allows one e-mail to be entered. Now I wanted to extend that and allow multiple mail-addresses to be added (just like MS Outlook, for example) with a semicolon as a mail-splitter.</p>
  
  <p><code>mail1@tld.com;mail2@tld.com;mail3@tld.com</code></p>
  
  <p>Now I've searched and found this one:</p>
  
  <p><code>([A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}(;|$))</code></p>
  
  <p>This works on one point, but sadly <strong>requires</strong> a semicolon at the end of a mail:</p>
  
  <pre><code>mail1@tld.com;
  </code></pre>
  
  <p>This is not what I want when the user only enters one e-mail.</p>
  
  <p>How can I extend my regex above (the first one) to allow multiple mail-addresses to be added while let them be splitted through a semicolon?</p>