How to export rigged character with ik or fk with .fbx format I want to export my 3d modal with ik in .fbx format. I also try this with export my rigged character with .fbx format but it`s IK is not working after import it again. 

One more problem is ik bone become double after import it in blender. I also check it in maya, there also same problem Ik not working.

Any one can tell me that, How can i export working ik or fk with .fbx.?
You cannot. Supporting basic bone animation is already a total nightmare, so we are not even remotely close to start dreaming about supporting things like constraints or IK in FBX (not totally sure FBX does support IK, actually…).