title: Forcing button control to run its client side before postback
body: <p>I have an asp button that is used to upload images (using uploadify) and it has also code
  behind . The problem is I want to run the client side script before postback. but the 
  postback occurs while uploading images .</p>
  
  <pre><code>&lt;ASP:BUTTON ID="Button1" runat="server" onclick="Button1_Click" onclientclick="Save();"/&gt;
  </code></pre>
  
  <p>How can I force it to finish the client script first ?</p>