Accessing dynamic web content is strictly prohibited in tvOS for the foreseeable future. Even if you find a way to hack around the restriction, the likelihood of the app being accepted into the tvOS App Store is nil.
There are a number of reasons Apple is making this stance, specifically:
• Apple can better control the quality experience of apps if they know exactly what content is going to be displayed
• Limit potential web exploits (phishing, viruses, etc.)
• Force developers to support native features and layouts
Though it appears like this may change in the future (see: https://twitter.com/ryanolsonk/status/642069462452056064).
Additional reading material on the subject: http://thenextweb.com/apple/2015/09/14/apples-made-it-difficult-to-build-tvos-apps-and-thats-good-for-users/