Need help! how can I link the nav menu in the same page with scroll down?

Answer 1

That's not a js related question but an html one.

I believe you mean like this? If not, feel free to precise your question.

<a href="#foobar">Link to some content on the same page</a>
<a name="foobar">The link will take you here</a>

Answer 2

actully I want to design everything on a single page.
like If I click on navigation menu:about.
so it take me into the footer area below.
http://www.pro-hosting.xyz there is an exmple of it.