I’m developing a Flutter application that uses a webview. While navigating from a DocuSign form and clicking back it displays this confirm navigation dialog (see below). It took me forever to find out this is a weird Android application confirmation screen and not a Flutter or DocuSign dialog. How can I prevent this dialog from displaying?

FYI: I’ve tried injecting JavaScript without success. I’m still getting this message even after injecting it onPageFinished of the webview.

Again is there a way to just block this message from ever showing up?

  void _injectPopupAvoidJavaScript() {
    const String js = """
      alert('test');
      window.addEventListener('beforeunload', function (e) {
        e.preventDefault();
        e.returnValue = '';
      });
    """;
    _webViewController.runJavaScript(js);
  }