Yes the modules does work in Firefox and IE.   You should be able to see it working on my site on the T-Minus page. 

However, T-minus uses the java-script timer function and depending on the implementation, and other modules on the page, T-minus may not get access to the timer function as some other module is using it.   The only solution is to place the T-minus on a page by itself - or remove the other timer based module from the page.  Scolling windows often use the timer to update the scroll window, so this may be the issue you encountered.

Paul.