Scenario: I am clicking through a game (via game replayer) on IE9, and I generate a diagram. The initial position appears to be correct. However, the FEN is incorrect. Thus if I flip the board, the diagram is incorrect (as flipping relies on the FEN). Frequently, generating the diagram in jpg format also fails (as the jpg generation process relies on the FEN, evidently).

Notes:

• I've noticed that the problem does not occur with Chrome.
• I would suppose that IE9 is implementing javascript a little differently than earlier versions of IE. Supposedly IE9 is more standards-compliant than earlier versions, but who knows?