How to insert any html-php page to a #container by clicking a link button

How to insert any html-php page to a #container by clicking a link button

Well here goes:
Say I have a home page it needs to be on display in the browser at all time, Even when I want to call in another page.  The correct place for the CLICKED-linked page is directed to the MAIN CONTAINER on the home page.
 
I've looked at many examples  but none seem to do this.
And when I use jquery the page clicked in the menu shows up on a completely new page.
It is supposed to show in the Container on the Home Page.
 
Also should my jquery code be inside the body tags or below the <head> tag?