Open a supported Facebook dialog. "feed" is just about the only useful one.
Specifies which dialog to show, such as "feed".
A dictionary object for pre-filling some of the dialog's fields. See example.
A callback for when dialog is completed/cancelled. The callback should accept a single argument which will be filled with a dictionary object concerning call results: items in the dictionary can be "success" (boolean), "error" (string with the error message), "cancelled" (set to true if user cancelled) and "result" (the data returned by Facebook.)