Apache redirect from any subdirectory to root

I would like to redirect user from any subdirectory like

example.com/abc
example.com/xyz/abc
http://ift.tt/1LpM7C4

to the content of root directory, but I would want this link to stay like that, so I can read it with JavaScript. So user types example.com/xyz, presses enter, is presented with whatever is in root catalog, but in address field he still sees example.com/xyz.

Also is it possible to block certain files so I can access them via AJAX requests, but not with direct links?