Clarification on multipage jquery sites

Clarification on multipage jquery sites

Hello,
I first posted this in the jQuery forum here: 


But was advised the JQM forum was a better place to start: 


I am new to jQuery, and I think the "problem" I am experiencing is down to simply how jQuery operates, but would welcome some clarification...
When I have a multi-page jquery site, interlinked with hyperlinks, then clicking on a hyperlink causes the URL to change, as one would expect, and for the new page to load. 
However, I have found that any javascript functions I want to call must have been included on the initial home page. For instance, if index.html links to page.html, then when I loade page.html from index.html I can not call a javascript function from within page.html that has been defined on that page. The definition must have been in index.html. 
This is fine, but a bit odd, and means that if the page.html page is ever linked to directly, then since the javascript functions are defined on the index page, they are now missing.


I was using basic hyperlinks initially. This seemed to load the source of the new page, but any javascript functions located outside of the standard jquery div structure were ignored. 
If, however, I included those same functions on the index page that was acting as the referer, all worked fine. 

I am now using:

$.mobile.changePage("filter.php?crs=" + crs);

Looking at the docs here:


It seems that this does indeed just reload the main page container, hence why the javascript doesn't function. 
What I don't quite understand is that if page2 is being loaded into the container div via an ajax call from page1, 
then how is it  that the URL in the browser address bar changes to that of page2...? Is it not, from the browsers point of view, always showing page1...?