code: function startOldBrowsersDetector(onOldBrowserDetected) {
    previousWindowErrorHandler = window.onerror;
  
    window.onerror = function oldBrowsersMessageShower(errorMsg, url, lineNumber) {
      if (onOldBrowserDetected) {
        onOldBrowserDetected();
      }
  
      if (previousWindowErrorHandler) {
        return previousWindowErrorHandler(errorMsg, url, lineNumber);
      }
  
      return false;
    };
  }
docs: Listens to unhandled errors and displays passed node