Right now, the application just hangs if you try to go to an invalid book or place URL (e.g. http://gap.alexandriaarchive.org/gapvis/index.html#book/spam). In these cases, it would probably be best to redirect to the index (for invalid books) or the book summary (for invalid pages), unsetting the relevant state variable.
Right now, the application just hangs if you try to go to an invalid book or place URL (e.g. http://gap.alexandriaarchive.org/gapvis/index.html#book/spam). In these cases, it would probably be best to redirect to the index (for invalid books) or the book summary (for invalid pages), unsetting the relevant state variable.