browsertime/browserscripts/browser/windowSize.js

Get performance metrics from your web page using Browsertime.

(function() {
  const w = window,
    d = document,
    e = d.documentElement,
    g = d.getElementsByTagName('body')[0],
    x = w.innerWidth || e.clientWidth || g.clientWidth,
    y = w.innerHeight || e.clientHeight || g.clientHeight;
  return x + 'x' + y;
})();