How to replace online data in web pages with offline data?

How to replace online data in web pages with offline data?

I run Firefox in my Windows 7 PC. There are a lot of web pages which
contain inline JavaScript as well as .js lnks nowadys. Some links may be
from inside, from that domain itself, while others are from outside, like
ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js. is it possible
to replace these links with offline data, stored in my local disk? That
is, when the browser calls for
ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js, the js may load
from my local disk like c:\jquery.min.js. Is this possible, at least with
Firefox, or is there any workaround / firefox addon or something like
that?
Thanks in advance.