Ajax could improve web page user experience by refreshing only part of the page rather than the whole page. So I believed the browser's URL could not be changed (except hash #) if the request was sent as an Ajax request, thus copying the URL from browser address bar to another browser window may not successfully re-open the page I am visiting. However I soon found I was wrong when I see GitHub web page.
When browsing repository folders in Github web page, it's not hard to find the page update is done by Ajax(debugged with Chrome). But the URL in address bar is also refreshed. So, what's the technology behind from Github web page for both updating page partially with Ajax and refreshing the URL in address bar?
