{% if site.google_plus_one %}
   <script type="text/javascript">
     (function() {
       var script = document.createElement('script'); script.type = 'text/javascript'; script.async = true;
       script.src = 'https://apis.google.com/js/plusone.js';
       var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(script, s);
     })();
   </script>
 {% endif %}