title: regex needed to strip out domain name
body: <p>I need a regexp to strip out just the domain name part of a url. So for example if i had the following url:</p>
  
  <p><a href="http://www.website-2000.com" rel="nofollow">http://www.website-2000.com</a></p>
  
  <p>the bit I'd want the regex to match would be 'website-2000'</p>
  
  <p>If you could also explain which each part of the regex does to help me understand it that would be great.</p>
  
  <p>Thanks</p>