Track browser size in Google Analytics (not just screen size)

gistfile1.js

/**
 * What this script will do is add a new tracking metric to work out the actual
 * size of a browser window (where as Google only tracks screen size). Goes
 * great with responsive design!
 * 
 * Adapted this from Zachstronaut (http://j.mp/RDztCB).
 */

_gaq = [
    ['_setAccount','UA-XXXXX-X'],
    ['_trackPageview'],
    ['_trackEvent', 'Browser Dimensions', 'Size', $(window).width() + 'x' + $(window).height()], // Track the browser width and height together
    ['_trackEvent', 'Browser Dimensions', 'Width', $(window).width(), $(window).width()],        // Track the browser width and get average
    ['_trackEvent', 'Browser Dimensions', 'Height', $(window).height(), $(window).height()]      // Track the browser height and get average
];

(function(d,t){
    var g=d.createElement(t),s=d.getElementsByTagName(t)[0];
    g.src=('https:'==location.protocol?'//ssl':'//www')+'.google-analytics.com/ga.js';
    s.parentNode.insertBefore(g,s)
}(document,'script'));