Optimizing the asynchronous Google Analytics snippet: mathiasbynens.be/notes/async-analytics-snippet

analytics.html

<script>
  (function(window, document, variableName, scriptElement, firstScript) {
    window['GoogleAnalyticsObject'] = variableName;
    window[variableName] || (window[variableName] = function() {
      (window[variableName].q = window[variableName].q || []).push(arguments)
    });
    window[variableName].l = +new Date;
    scriptElement = document.createElement('script'),
    firstScript = document.scripts[0];
    scriptElement.src = '//www.google-analytics.com/analytics.js';
    firstScript.parentNode.insertBefore(scriptElement, firstScript)
  }(window, document, 'ga'));

  ga('create', 'UA-XXXX-Y');
  ga('send', 'pageview');
</script>

analytics.js

(function(G,o,O,g,l){G.GoogleAnalyticsObject=O;G[O]||(G[O]=function(){(G[O].q=G[O].q||[]).push(arguments)});G[O].l=+new Date;g=o.createElement('script'),l=o.scripts[0];g.src='//www.google-analytics.com/analytics.js';l.parentNode.insertBefore(g,l)}(this,document,'ga'));ga('create','UA-XXXX-Y');ga('send','pageview')