How does the github user interface navigate directories without postback?

Question

When navigating my repo directories on github.com, I noticed that it uses cool javascript effects to switch between the types of directories without causing a postback, and yet the URL changes beautifully and RESTfully: http://../tree/master/dir7→ http://../tree/master/dir7/dir4.

Whenever I have to track navigation using javascript, I always had to resort to hash arguments in the address bar. http://...page#new-javascript-location

How do they do it?

Answer 1

https://github.com/blog/760-the-tree-slider