title: Add parameter to url
body: <p>I have a url (e.g. <a href="http://www.youtube.com/watch?v=og9B3BEnBHo" rel="noreferrer">http://www.youtube.com/watch?v=og9B3BEnBHo</a>) and I'd like to add a parameter to it (wmode=opaque) so that its:</p>
  
  <p><a href="http://www.youtube.com/watch?v=og9B3BEnBHo&amp;wmode=opaque" rel="noreferrer">http://www.youtube.com/watch?v=og9B3BEnBHo&amp;wmode=opaque</a></p>
  
  <p>Can anyone tell me which function to use to make this work?</p>