Check if the user is on Facebook

Question

Check if the user is on Facebook

I'm looking for a way to check if people shared on Facebook. After they are shared, they will be redirected to another page.

So far I have found the code below. It will present the same page to the user. When they click on it, they can share something too. The problem is that edge.create will get a response before something is distributed. Thus, he checks only for him, not for a share.

Is there any way to check if the user has shared?

Thanks!

    <html>

<div id="fb-root"></div>
<script>
  window.fbAsyncInit = function() {
    FB.init({
      appId      : 'ID', // App ID
      status     : true, // check login status
      cookie     : true, // enable cookies to allow the server to access the session
      xfbml      : true  // parse XFBML
    });

    FB.Event.subscribe('edge.create',
   function(response) {
        window.open ('page.html,'_self',false)    
   }
); 
  };

  (function(d){
     var js, id = 'facebook-jssdk'; if (d.getElementById(id)) {return;}
     js = d.createElement('script'); js.id = id; js.async = true;
     js.src = "//connect.facebook.net/en_US/all.js";
     d.getElementsByTagName('head')[0].appendChild(js);
   }(document));
  </script>

  <fb:like href="http://www.youtube.com/watch?v=WJTXDCh2YiA" 
     send="true" width="450" show_faces="false"
     >
</fb:like>
</html>