If logged in fb show message

[Vaonline]

Hello.
I am looking that the visitors already logged in facebook that comes to my webpage gets an extra message like "You are logged in facebook" or "Welcome $FBUSERNAME"
I have been looking to tutorials on facebook help page but i dont see an end to this. I have to say that its not an app issue, its for my website.
Does somebody knows how to do it?

Thanks

[Beverleyh]

I haven't tried personally but this looks promising : http://www.tomanthony.co.uk/blog/detect-visitor-social-networks/

[traq]

Your website can be a FB app. If you want to integrate with FB, I think that would be the most sensible approach. You could also use Oauth. Either approach would require the user's consent before you could know their login status/ user info (which is as it should be).

The hack that Beverly pointed out is workable, but might not be for long. "Undocumented" behaviors are undocumented for a reason: they're not intended to be consumed, and might change without notice. On top of it, it smells like hacking (technically is hacking, even if it's not malicious), so it might earn you FB's wrath if they find out about it.