Nobody else seems to have posted this, so I will: The current CSS3 Fonts Module provides a syntax to use CSS to declare use of a few dozen OpenType properties. If I have the list correct, they are:
Remember: This is merely a proposal. CSS3 has been broken into modules so that that makers of browsers (etc.) can pick and choose which modules to support rather than being offered a package deal of every single CSS feature, which, experience proves, is too much to handle at once. (Hence it is impossible to state that a browser “supports CSS3.”)
Nonetheless, this is surely a useful development. The acknowledgements on the page will reveal a few Usual Suspects.