Firefox is often unresponsive after waking up/resuming from hibernate/suspend on Ubuntu 12.04. After a while it will give me an error saying that some script is unresponsive and I get the choice to 'Stop' it or 'Continue' running it:

A script on this page may be busy, or it may have stopped responding. You can stop the script now, or you can continue to see if the script will complete.

I guess that Firefox doesn't like active scripts to be interrupted by hibernate/suspend, and thus freezes once I wake-up/resume my laptop. How do I resolve this, in order to make Firefox wake-up happy and snappy again?