Don’t tell me what my browser can’t do! by Christian Heilmann
A great piece by Christian on taking a responsible, customer-focused approach to building on the web.
You don’t have to support old browsers and terrible setups. But you are not allowed to block them out. It is a simple matter of giving a usable interface to end users. A button that does nothing when you click it is not a good experience. Test if the functionality is available, then create or show the button.