counter does not work on preview

I haven't been able to test this under a variety of different circumstances, but thought you would like to know that I've never seen it work on previews before items are saved. It displays NaN - so somehow the javascript must be getting the wrong number. I've simply made the preview buttons disappear for content types that use this module, so not a very big deal for me. Browser: Firefox 2 (old, I know - I'm sort of late in getting apt sorted out), theme: custom based on zen.