Ajax loading problem L4.2

I try to make dependent dropdown list. Imade it in very long way using my route controller and javascript my problem is when i choose a country in state option showing all state related to that country but we have to manually again select state for next option(district) my view http://laravel.io/bin/bE7Nx and my javascript http://laravel.io/bin/XyOYy and my controller http://laravel.io/bin/Nk3YV and my route http://laravel.io/bin/E3LYm any can help me?