An AssetWebSurface defines an interactive surface that provides a 2D web view. Note that this surface can be placed on an Object by specifying a websurface_id that matches the AssetWebSurface's id.

http://janusvr.com/docs/build/assetstag/index.html#AssetWebSurface

src - The website to assign to this asset.
width - The horizontal resolution.
height - The vertical resolution.
show_url_bar - Whether or not to show navigation controls on this asset.