Callback URL for digg button

I am working on a website where the client has asked me to implement a functionality where a part of the content is shown to the end user once the page is liked by the end user on Facebook or the user had clicked on digg share button.

I have implemented a callback successfully which shows the content after the facebook button is liked. The way I did it is like this:

<div id='fb-root' style=''></div> <fb:like href='URL to like' show_faces='false' border_color='' stream='false' header='false'></fb:like-box><script type='text/javascript'>

         window.fbAsyncInit = function() {
        FB.init({appId: 'APP ID', status: true, cookie: true, xfbml: true});
        FB.Event.subscribe('edge.create',
            function(response) {

        alert ('You clicked the facebook button');


        // Other javascript to be executed can be placed here.          


            }
        );

    };


    (function() {
        var e = document.createElement('script'); e.async = true;
            e.src = document.location.protocol +
              '//connect.facebook.net/en_US/all.js';
            document.getElementById('fb-root').appendChild(e);
    }());
</script>

The alert in the above code only gets executed when the callback confirms that the user has clicked the facebook like button.

I am trying to do something similar with Digg as well. I searched there API but I was not able to find a solution to such problem.

In simple words I want to know if there is a callback which confirms that the user has clicked the diggshare button ?

Thanks and any help would be appreciated.

Digg is not having any such callback thing. Came to me as a disappointment !