minibrowser attributes for devices

Is there a listing somewhere where one can find what attributes work on different devices. For example, I have been playing with a WML page, and viewing it with my nextel phone, however, none of my <i></i> text is showing up at italics... It shows up, just not italicized. I would like to see what other devices have this problem, and what other tags/attributes are missing from different minibrowsers.

Thanks for your help,

Mike