I've written this type of script before - I didn't need too much in the way of debugging. Mine (similar to GP, it seems) didn't actually do the registration, just save the current state of known divs or even the whole page. Then it would send me an update if that changed.
So, I didn't need to debug what happens when the class shows "open" - I just saved the div that said "closed" and sent myself an email/text any time it didn't say exactly that.
So, I didn't need to debug what happens when the class shows "open" - I just saved the div that said "closed" and sent myself an email/text any time it didn't say exactly that.