CPU load stuck at 100% with Chrome and Firefox

[nachokb]

Tested on Ubuntu 13.04 (Rhythmbox 2.99.1 is running in another computer, with a beta of Saucy 13.10), on both Google Chrome and Firefox.

Here's a Chrome profiling dump => http://ubuntuone.com/6DEsJHKDyMXpzhOcGHPPqk

It shows that the GET /playerinfo callback killing it... this is a long function so I haven't analyzed much, but the culprits seem to be line 163 and 211 (~50% each).

Line 163 just hides the Play button (as it is in play state), I fail to see why that triggers a ~1 sec "recalculate style" event.

Line 211 calls jQuery mobile's listview('refresh')...

[nachokb]

$playButton.hide() affects 19k elements.... my library has 29k files, perhaps it's related? ($playButton.length == 1 though)