$ sudo apt-get update
$ sudo apt-get install js-of-ocaml 

js-of-ocaml is installed in your system.

Make ensure the js-of-ocaml package were installed using the commands given below,

$ sudo dpkg-query -l | grep js-of-ocaml *

You will get with js-of-ocaml package name, version, architecture and description in a table

js-of-ocaml package basic information: