Use the network inspection tools of your browser to see what data actually gets sent or retrieved. From the looks of it, some data is passed to some fileTree plugin for jQuery, and most likely somewhere else in the HTML, that data is fetched or it is fetched when clicking on a link.

As an alternative, you could try to use Perl to automate your browser, for example using WWW::Mechanize::Chrome or WWW::Mechanize::PhantomJS.