Autologin with Inappbrowser on an external website?

I've built a native app with Phonegap Build. Is there a way to autologin in webview on an external website (embedded with inappbrowser).

The app starts and then the users will be redirecting to the website for login. But the users have to put in their username and password again and again. is there a possibility to autologin? Ive read about localstorage. Is that possible with the inappbrowser on a external website (there is no access to the phonegap plugins I know).