popup, a browser popup window
is used. This is necessary for identity providers that refuse to
open inside a frame. The default is iframe, which handles
the login inside an iframe element in a modal popup.
The Item is often an image. The image must have a class
login-with. Below is an example to login with Google:
swish_config:login_item(Item) :-
http_absolute_location(icons('social_google_box.png'), Img, []),
Item = img([ src(Img),
class('login-with'),
'data-server'(google),
title('Login with Google')
]).