I want that some sections on my page to remain (like header, footer) and only the main content to change. In the same time, the URL should also change, according to the new content.

I know all about AJAX/iframes but I don't want to use them as the URL remains the same.

Take a look please at [123contactform.com](http://www.123contactform.com/tour.html). Try to play around with the left menu and notice that the main content changes and also the URL (while the header, menu, footer stays).

How is this achieved?

Thanks.