Function isSameOriginFrame

docs/external/js/react-dom.development.js:7045–7058

(iframe)

  }

  function isSameOriginFrame(iframe) {
    try {
      // Accessing the contentDocument of a HTMLIframeElement can cause the browser
      // to throw, e.g. if it has a cross-origin src attribute.
      // Safari will show an error in the console when the access results in "Blocked a frame with origin". e.g:
      // iframe.contentDocument.defaultView;
      // A safety way is to access one of the cross origin properties: Window or Location
      // Which might result in "SecurityError" DOM Exception and it is compatible to Safari.
      // https://html.spec.whatwg.org/multipage/browsers.html#integration-with-idl
      return typeof iframe.contentWindow.location.href === 'string';
    } catch (err) {
      return false;
    }
  }

  function getActiveElementDeep() {
    var win = window;