From Facebook Developer Wiki

How do you use this in a FBML / PHP application?

You can run it in your code to pop up a Feed dialog. You can see an example of it in Smiley, our sample app: http://svn.facebook.com/svnroot/platform/samples/smiley/js/base.js Pete (563683308 15:34, 17 September 2009 (PDT))