Web client communication

probably an obvious thing, but I am not getting it somehow…
In order to get an understanding of the web client, I did both Fiddler and Firebug tracing. However, it does not capture any communication, when I click controls in Now Playing or when browsing local files in Browse.
When I start playing a local mp3 file, I can see calls to last.fm and audioscrobbler.net. Those retrieve meta data for the song being played (incl. album cover image).
But I would expect to see some XHR when browsing the local files or pausing a song. I am confused.
How would I capture such requests?
Thanks in advance,


Trick is that we use websockets, I have no idea if firebug or fiddler support these, but I do know that chrome/chromium debug tools will show you this communication channel and json-rpc messages being sent.