Why isn't this "ajax:success" event firing?
===

I have a view with several "Invite" buttons like this:

			<div class = "fbinvite_form" id = "<%= friend[:identifier] %>" name = "fb">
				<div class = "btn btn-small">
					Invite
				</div>
			</div>

When one of these buttons are clicked an AJAX function is called (invite_friend) :

    $('.fbinvite_form').click(function() { invite_friend(); });

Here's invite_friend (some values are hard-coded as I debug):
 
    function invite_friend() { 		
	$.post('/groups/7/invitations', { "recipient_email": "facebook@meetcody.com", "commit" : "fb", "fb" : "fb" }, function(response) {
	});}

Here's the relevant line that is returned from the controller:
           
    render :json => {:url => signup_with_token_url(@invitation.token), :id => @invitation.id }, :status => :created

I can confirm that this json is being rendered correctly. At this point I'm expecting an "ajax:success" event to fire. I have the following code at the top of my page:

    $('.fbinvite_form').bind("ajax:success", function(evt, data, status, xhr){ ... });

But it's not firing. Any clue what might be going wrong or how to better troubleshoot (I'm a bit of a noob)?
