Snippets

(function(doc, script) {
  var js,
      fjs = doc.getElementsByTagName(script)[0],
      frag = doc.createDocumentFragment(),
      add = function(url, id) {
          if (doc.getElementById(id)) {return;}
          js = doc.createElement(script);
          js.src = url;
          id && (js.id = id);
          frag.appendChild( js );
      };

    // Google+ button
    add('https://apis.google.com/js/plusone.js');
    // Facebook SDK
    add('//connect.facebook.net/en_US/all.js#xfbml=1&appId=200103733347528', 'facebook-jssdk');
    // Twitter SDK
    add('//platform.twitter.com/widgets.js');

    fjs.parentNode.insertBefore(frag, fjs);
}(document, 'script'));