title: How do I interrupt an ASP.NET button postback with BlockUI and Jquery
body: <p>I have an ASP.NET page with a number of ASP:Button instances on it. For some, I need to show a confirmation prompt and, should the user choose yes, the original postback method is called. Otherwise, the overall process is cancelled.</p>
  
  <p>I've got an example running but I get inconsistent results, mainly in FF3 where I get an exception thrown:</p>
  
  <pre><code>[Exception... "Illegal operation on WrappedNative prototype object"  nsresult: "0x8057000c (NS_ERROR_XPC_BAD_OP_ON_WN_PROTO)"  location: "JS frame :: 
  </code></pre>
  
  <p>I've looked this error up but I'm drawing a loss as to where I'm going wrong. Here's my example case. Note, for now I'm just using the css class as a lookup. Longer term I can embed the clientID of the control into my JS if it proves necessary :).</p>
  
  <p>Html fragment:</p>
  
  <pre><code>&lt;asp:Button ID="StartButton" runat="server" CssClass="startbutton" Text="Start" OnClick="OnStartClicked" /&gt;
  </code></pre>
  
  <p>Javascript:</p>
  
  <pre><code>$(".startbutton").each(function(){
              $(document).data("startclick", $(this).get()[0].click);
              $(this).unbind("click");
          }).click(function(){
              var oldclick = $(document).data("startclick");
              alert("hello");
              try
              {
                  oldclick();
              }
              catch(err)
              {
                  alert(err);
                  alert(err.description);
              }
              return false;
          });
  </code></pre>
  
  <p>My code behind is relatively simple, the OnStart method simply executes a Response.Write</p>
  
  <p>I've only just started looking into bind, unbind and trigger so my usage here is pretty much 'first time'.</p>
  
  <p>Thanks for any help or advice.</p>
  
  <p>S</p>
  
  <p>EDIT:</p>
  
  <p>This describes what I'm trying to do and also gives a run down of the kind of pitfalls:</p>
  
  <p><a href="http://www.nabble.com/onClick-prepend-td15194791s27240.html" rel="nofollow noreferrer">http://www.nabble.com/onClick-prepend-td15194791s27240.html</a></p>