title: How are the facebook chat windows implemented?
body: <p>On <a href="http://www.facebook.com/" rel="nofollow noreferrer">Facebook</a> you can browse the site without affecting the floating chat windows. Seems like if the main page was inside an iFrame and the footer and chat windows where floating outside.</p>
  
  <p><a href="https://i.stack.imgur.com/Ay9zD.gif" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Ay9zD.gif" alt="alt text"></a><br>
  <sub>(source: <a href="http://www.k-director.com/blog/upload/FacebookChat03.gif" rel="nofollow noreferrer">k-director.com</a>)</sub>  </p>
  
  <p>Is the main content inside an iframe or are the footer and chat windows the ones inside an iframe? </p>
  
  <p>The later doesn't seem possible because int this case when you click in a link in the main page everything would have to reload, including the footer iframe.</p>
  
  <p>If you refresh the page the chat windows are reloaded, but if you browse the site by clicking links they are not.</p>
  
  <p>Thank you.</p>