title: How does an UpdatePanel actually work?
body: <p>What is updated when an Update is triggered? What goes to the server? What comes back?</p>
  
  <p>I was under the impression that only the content of the panel was transmitted to the server and back (without touching anything in the page outside the panel), but I'm experiencing strange results, probably because I don't really understand how it works exactly.</p>
  
  <p>Can someone provide an easy explanation as to how exactly it works?</p>