I don't think we should do this. We already clearly indicate in the inspector when a value is ignored. We don't need to spam the console with warnings.

@Ojan: We've had the idea of logging various CSS-related messages (see bug 19236) in the air for a while. While spamming the console is definitely wrong, some kind of notifying the user about broken stylesheets can be useful. I just checked the latest Opera Dragonfly, and they have a special "Errors" panel (using our terms) where they show errors that encountered while processing the page resources, broken down by categories (including "CSS"). This can be a kind of implicit audit, so that the user will not have to check all their matched styles to see bad properties. And of course, it should be possible to avoid logging certain vendor-prefixed properties (-moz-* et al.)

(In reply to comment #2) > @Ojan: We've had the idea of logging various CSS-related messages (see bug 19236) in the air for a while. While spamming the console is definitely wrong, some kind of notifying the user about broken stylesheets can be useful. > > I just checked the latest Opera Dragonfly, and they have a special "Errors" panel (using our terms) where they show errors that encountered while processing the page resources, broken down by categories (including "CSS"). This can be a kind of implicit audit, so that the user will not have to check all their matched styles to see bad properties. And of course, it should be possible to avoid logging certain vendor-prefixed properties (-moz-* et al.) Ah yes. This makes a lot more sense. Something with a dedicated UI seems reasonable.