javascript - How AJAX is done in github source browse?

Question

Github has a really nice source browser. Navigating between different paths in the repo generates ajax calls to load the content (as you can clearly see in the firebug log). The ajax call returns the html of the new list of files to be displayed. In addition to changing the view list of files, the url changes as well. However it does not use fragments like most ajax deep-linked sites (use of #). At github the whole url changes.

For example at django repo at https://github.com/django/django going to django folder will generate ajax request to https://github.com/django/django/tree/master/django?slide=1&_=1327709883334 which will return the html content of the folder. The link will also change to https://github.com/django/django/tree/master/django. As you can see this new link does not use a fragment.

How is that done? I always thought that ajax based sites have to use url fragments (#) to achieve deep linking but apparently it is not so.

Answer 1

You have to use HTML5's pushState() method to change browser history.

window.history.pushState(data, "Title", "/new-url");

Doc says:

pushState() takes three parameters: a state object, a title (which is currently ignored), and (optionally) a URL.

The last argument is the new URL. For security reasons you can only change the path of the URL, not the domain itself. The second argument is a description of the new state. And the first argument is some data that you might want to store along with the state.