title: Handling presence in Strophe.js-based chat application
body: <p>Is there any existing solution which provides the presence handling for chat app based on Strophe.js?</p>
  
  <p>I have simple chat application based on Strophe.js. I'd like to show only the users who are online and dynamicaly alter the list. I was wondering whether there is any existing solution (possibly Strophe plugin) which handles this. If there's no such thing, what's the best/simplest way to implement it? </p>