webchromeclient is a kind of extension for webview. it handles tasks that webview is not designed to do.
one of these tasks has to do with asking the user for runtime permission: camera, location, etc. a dialog
pops up on the browser screen asking for permission to use these features. apparently, permission to
use nfc is not currently supported by webview. webview's chromeclient does not respond to a request
from the server to use nfc. permission is not granted. the server's javascript posts the error. i assume it
is a matter of updating android's webview (and its extensions).
while it is possible to make chromeclient grant permission to a request programmatically (not recommended
for security reasons), it is probably not possible to grant permission for which there was no recognized request.
i have an idea; i need a little time to look through an old project. i'll let you know. maybe today.
sorry, it doesn't appear what webchromeclient is asked to grant permission for nfc (at this time).
by the way, you could try adding "android.permisson.NFC" to your manifest, but i'd be surprised if it made any difference.
it's not a "dangerous" permission for android, like location.
i can tell you webviewextras won't work in this case. there are some other webview libraries you could try. i'm not
very familiar with them. they would have a webchromeclient and an event in b4a to handle permission requests.
---------------------------------------- update -----------------------------------------------------------
so i tested with the web nfc api in a webview. see attached. technically, webchromeclient says nfc is supported
but there is no way to grant the permission since it's not asked for
. that's the holdup. see the log message on the right