How do I do make a navbar like slides to the pertaining area like this?

I know, "this" isn't very specific, but it's hard to describe in a title so I'll show you an example.

http://purplefront.com/

In this single-page website, pressing the links in the navbar scrolls you down to the area of the website that pertains to the aforementioned link. The navbar also shows where you are in the page by highlighting the heading in the navbar.

I think it uses Jquery, but I'm not very sure, and I'm not so good at Jquery either.