I want to add Page DEPENDENT Navigational menus to my site

I was looking at a JS based dynamic menu … which will probably work but adds more dependencies.
https://github.com/swisnl/jQuery-contextMenu

And then it hit me. What if i add Context-Nav sub menu in the main menu OR as a widget on the right (not ideal, but).

The problem is that it has to DEPENDENT on which page I’m at the moment.

How do I do that ?