How can one check on server if Opera Mini is running in saving mode? I don't see Opera Mini in User Agent string anymore, even in extreme saving mode. And HTTP_X_REQUESTED_WITH is always the same - com.opera.mini.native.

We have problem with Opera Mini, it fails to execute any Javascript on the page after "Uncaught SecurityError: Blocked a frame with origin "http://origin" from accessing a cross-origin frame.", when other browsers do not have such error. Moreover without saving mode Opera Mini works just fine without such error.