SuzyUK - 12:56 pm on Mar 1, 2011 (gmt 0)
just a note if you saw this in mid-edit - I made a mistake in my original post so the choices at the end have changed, however I'm not allowed to edit any more, so to clarify one point..
when I say "fairly impossible" I mean specifically with interactive pages it's not always possible to ensure a classname is not reused, and it's likely dangerous just to blindly assume that because your classes are only used once (like an ID) on your page that removing the qualifying element will be enough.. it might break a page later on down the line. Some widget you install at a later date might use the same class names.. usually this is not the case with ID's as widgets make sure their ID's are "namespaced" i.e. very particular to their code to ensure there's not a clash .. hence my advice to use ID's if unsure. Your ID's as well as still being unique(hopefully ;))- will likely not be the same, as specific as, plugged in code is likely to be, their best practices mean their id's are usually prefixed with "mywidget" e.g. #mywidget-left