获取自定义的全局变量

getGlobalVars.js

(function() {
  var keys = [];
  var iframe = document.createElement('iframe');
  iframe.onload = function() {
    var iframeKeys = Object.keys(iframe.contentWindow);
    Object.keys(window).forEach(function(key) {
      if (!(iframeKeys.includes(key))) {
        keys.push(key);
      }
    });
    console.log(keys);
  };
  iframe.src = 'about:blank';
  document.body.appendChild(iframe);
})();