How to detect if my site is in Facebook iframe or standalone site

I want to programatically detect if my site is within the Facebook iFrame app so I can display certain f开发者_运维技巧eatures specifically for Facebook. Otherwise if someone goes site without Facebook. Preferably an FBML, C# or JS solution would be great :) Thx!

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Well, you can always go with the basic javascript check for whether or not a page is framed

if ( top === window )
{
  // page is not framed
}

Also, when a user first hits your canvas page, the Facebook platform sends a bunch of data to your callback url, either in normal GET parameters or in a single, encoded parameter (depending on your settings) which you can also check for.