Auto Login WebView AndroidStudio

Question

i have try this code and its work for auto fill fields , but whene i click for login buton the fillds of ema and pw become impty

public void onPageFinished(WebView view, String url) {
  super.onPageFinished(view, url);
  web.loadUrl("javascript:(function() { document.getElementById('id_userLoginId').value = '[email protected]'; ;})()");
  web.loadUrl("javascript:(function() { document.getElementById('id_password').value = '889988'; ;})()");
  System.out.println("AUTOFILL");}