title: Fix Regular Expression for Emails to Not allow Consecutive Periods
body: <p>my regular Expressions are pretty bad so I thought  would look for some help on this.</p>
  
  <p>I have a regular expression:</p>
  
  <pre><code>/[a-z0-9!#$%&amp;'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&amp;'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?/;
  </code></pre>
  
  <p>and it works for most cases of my email validation however it allows this one through:</p>
  
  <p>test..testing@gmail.com</p>
  
  <p>How would I alter the above Regular Expression to not allow consecutive periods anywhere throughout the string?</p>
  
  <p>Thanks.</p>