Providing simple shell scripts to accompany jailfox
git clone https://github.com/ddowse/jailfox-install
cd jailfox-instal
su
./install.sh TARGET [ PATH ]
PATH
is the path on your host e.g /usr/home/foobar/Downloads
that should be
mounted as the download directory for Firefox inside the jail.
jailfox
In sudoers (visudo) for example:
%wheel ALL=(ALL) NOPASSWD: /usr/local/libexec/jail-firefox-exec