title: How to make the content of the popup make a PostBack only when it's appeared
body: <p>I have a user control is shown through a <code>SimpleModal</code> popup (JQuery), this user control gets some data from database and displays them (the details of a record).</p>
  
  <p>The problem is that this user control makes a round-trip to gets the data every PostBack for the parent page even it's hidden.</p>
  
  <p>I wonder if I could make it gets its data only if the popup is appeared.</p>
  
  <p>I tried to put it inside a <code>Panel</code> with <code>false</code> for <code>Visible</code> property and change it to <code>true</code> when I open the popup, but it stil call Page_Load which gets the data from database!</p>
  
  <p>Any idea !!</p>