Earlier quoted context omitted.
A warning is fine, but I just hate it when a site doesn't even let me try in another browser. I use Firefox Nightly, maybe it fixed the issues that are breaking your app? If you're detecting via user agent, what if I use an odd user agent? What if I want to look at the web console to see just what breaks in case I know what the issue is?
> I use Firefox Nightly, maybe it fixed the issues that are breaking your app? If it's using -webkit prefixed CSS, that's pretty unlikely. > What if I want to look at the web console to see just what breaks in case I know what the issue is? Anyone interested in doing that should be well aware of how to spoof a user agent.
Unsupported CSS features should not affect the functionality of a web app, only its appearance. Emphasis on "should"; far too many web apps end up fundamentally broken when this happens.