Log global variables

globals.js

// Based on https://davidwalsh.name/global-variables-javascript

(function logGlobals() {
  var iframe = document.createElement('iframe');
  iframe.onload = function() {
    var iframeKeys = Object.keys(iframe.contentWindow);
    var windowKeys = Object.keys(window);
    
    windowKeys.forEach(function(key) {
      if (iframeKeys.indexOf(key) === -1) {
        console.log(key);
      }
    });
  };
  iframe.src = 'about:blank';
  document.body.appendChild(iframe);
})();