> I just assumed that hiding error in unsupported browsers would be better than having unhandled exception.

I can understand that. Over time I came to prefer explicit/transparent approaches to this situation. My argument would be that "function does not exist" is more clear when debugging why something doesn't work, rather than awkward offsets without any error. But what's more important is what side-effects can that un-handled exception have, do you think it can affect other components from a website that includes Dragdealer and is opened in a prehistoric browser?