title: Is there some equivalent to setInterval in the ZK server structure?
body: <p>I'm trying to make a process that will refresh my Chart from time to time. In <code>Javascript</code> the answer comes in my mind: <code>setInterval()</code> + ajax call. How can I do this with ZK?</p>
  
  <p>I looked at the <a href="http://books.zkoss.org/wiki/Small_Talks/2010/April/Client_Side_Programming" rel="nofollow">Client Side Programming</a> but didn't find anything that solves this requirement.</p>
  
  <p>In the Server Side, it seems that I can fire events with <code>Events.echoEvent()</code>, doing this repeatdly have any downside?</p>