monline

Initially I've found this Bugzilla entry which explains how recent changes in the Mozilla codebase "interfere" (as a sideeffect to some optimizations) with the timers -ie. countdowns- on fileserve.com, freakshare.com and netload.in (and possibly on a couple of different sites). If you start a timer/countdown in one tab and switch to another, the timer stops (to be more precise: slows down virtually to a halt). If you switch back to the tab, the timer continues where it left off.

This is quite an annoyance for visitors of these sites since it prevents the running of the countdowns in a background tab. As far as I could tell, the current version of Firefox (4.0.1) and Safari (5.0.5) don't have any problems with these timers in background tabs, but Chrome 11.0.696.57 already does ... since Chrome developer implemented a similiar optimization.