pixel fb

<script>

  window.fbAsyncInit = function() {

    FB.init({

      appId      : '{your-app-id}',

      cookie     : true,

      xfbml      : true,

      version    : '{api-version}'

    });

    FB.AppEvents.logPageView();   

  };

  (function(d, s, id){

     var js, fjs = d.getElementsByTagName(s)[0];

     if (d.getElementById(id)) {return;}

     js = d.createElement(s); js.id = id;

     js.src = "https://connect.facebook.net/en_US/sdk.js";

     fjs.parentNode.insertBefore(js, fjs);

   }(document, 'script', 'facebook-jssdk'));

</script>