code: function startPollingForErrors() {
      var checkFunction = (function() {
          // For an unknown reason, page.evaluate does not always load the function in the top window,
          // but can sometimes load it in an iframe inside the page...
          var topWindow = window.top;
          if (!topWindow.attester) {
              topWindow.console.log("Autoexit check error: attester does not seem to be correctly loaded!");
              topWindow.callPhantom({
                  name: "attesterOnDisconnect"
              });
          } else if (!topWindow.attester.connected) {
              topWindow.console.log("Autoexit check error: attester does not seem to be connected!");
              topWindow.callPhantom({
                  name: "attesterOnDisconnect"
              });
          }
      }).toString();
      setInterval(function() {
          page.evaluate(checkFunction);
      }, autoexitPolling);
  }
docs: Checks for errors in the opened page every 'autoexitPolling' milliseconds, this value can be controlled by the
  command line parameter --auto-exit-polling=x