I've navigated a lot through the github website. I've observed that whenever I click on a link, the page does not refresh and even the URL in the browser is changed. Moreover, those links are added in the history!
Well, I know that AJAX is a way to go and I know a lot of JavaScript(semi-intermediate level coder) but you can't change the URL with Ajax. Neither can you make those URLs be visible in the history.
So, how the heck do they do it?