I did integrate identity manager in our app.
Without using https in our app, I have no problem to GET https for the ArcGIS online authentication token in both IE10 and Chrome.
I do have problem in IE 9-.
It seems that I have to setup proxy page to do so in IE9-.
I guess the reason proxy page is not needed in IE10 and latest Chrome, is because they support CROS.
But I have no idea why the demo requires to access itself through https even use IE 10 though.
It may be related to app server setting.
Thanks,
Tony