How to « find deep » and « get parent » in JavaScript nested objects with recursive functions and the reference concept (level : beginner)

Working with nested objects is frequent in JavaScript ; so I made this screen cast around this question. But the goal here is to help JavaScript beginners to understand how to build a simple recursive function and to get a better intuition about the reference system in JavaScript. The full text contents is in the post and you have also a fiddle to play with the code and see it in action.