Android Question Webview with sqlite local database.

I am trying to create an activity with a webview. (my app: b4a + html5 + jquery mobile).

This webview loads a html file with WebSQL database.

In desktop works well (google chrome)

android:
Webview not open/create the file database.

var db = window.openDatabase... always return null.

I've used the webviewsettings library to set the webview in b4a but not worked.

Any idea?

Excuse my English.

Thank you.