performance issue in firefox 9.0.1 on ubuntu 10.04

[Abe404]

I am finding the game runs very slowly and then pretty much grinds to a hault in firefox 9.0.1 on ubuntu 10.04

The character does not move immediately after a key is pressed due to a lag which increases until the browser freezes.

I have been testing/developing in firefox 3.6.25 thus far and have found the game to run ok. It was only after upgrading to firefox 9.0.1 that the problem occurred.

The machine is a fairly low performance dell inspiron mini 9 (dual core 1.6ghz 2gig ram)

My tests show so far that the problem does not occur on:
chromium 15 on ubuntu 10.04 (same machine)
firefox 3.6.25 on ubuntu 10.04 (same machine)
firefox 9.0.1 on windows 7 (different more powerful machine)
chrome 16 on windows 7 (different more powerful machine)