Find global variables in the browser, discover global variables a web side is exposing in JavaScript

globals.get.js

/*
    Usage

    global.get() // return Array of globals found
*/

;(function (global) {

  function Globals () {}

  var getWindow = function () {
    var iframe = document.createElement('iframe')
    iframe.style.display = 'none'
    document.body.appendChild(iframe)

    var result = iframe.contentWindow || iframe.contentDocument

    iframe.parentElement.removeChild(iframe)

    return result
  }

  Globals.prototype.get = function() {
    var iframeWindow = getWindow()
    var result = []
    var property;

    for (property in global) {
      if (!(property in iframeWindow)) {
        result.push(property)
      }
    }

    return result
  };

  global.globals = new Globals();

}(window));