You can uninstall or removes an installed js-of-ocaml package itself from Ubuntu 12.04 LTS (Precise Pangolin) through the terminal,
$ sudo apt-get remove js-of-ocaml
If you would like to remove js-of-ocaml and it's dependent packages which are no longer needed from Ubuntu,
$ sudo apt-get remove --auto-remove js-of-ocaml
If you use with purge options to js-of-ocaml package all the configuration and dependent packages will be removed.
$ sudo apt-get purge js-of-ocaml
If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.
$ sudo apt-get purge --auto-remove js-of-ocaml