How cool!
I got a generic USB gamepad and it worked fine.
Windows 7 32bits
Firefox Nightly 11.0a1 (2011-12-12)
Detected as "Gamepad 0 ID 810-3-USB Gamepad"
Analog mode ON
Buttons in the following (correct) order:
B1, B2, B3, B4,
Left shoulder button, Right shoulder button,
Left shoulder trigger, Right shoulder trigger,
back, Start, Left stick, Right stick.
Axis maps as follows:
Left Stick left/right (X) = Axis 0, -100..100
Left Stick up/down (Y) = Axis 1, -100..100
Right Stick left/right (Z axis) = Axis 5, -100..100
Right Stick up/down (Z rotation) = Axis 2, -100..100
D-pad left/right = Axis 5, -100/100
D-pad up/down = Axis 6, -100/100
Analog mode OFF
Buttons in same order, but stick ones don't work.
Axis 0 and 1 read -1 when idle.
Axis maps as follows:
Left Stick left/right (X) = Axis 0, -100/100
Left Stick up/down (Y) = Axis 1, -100/100
Right Stick left/right (Z axis) = buttons 3, 1
Right Stick up/down (Z rotation) = buttons 0, 2
D-pad left/right = Axis 0, -100/100
D-pad up/down = Axis 1, -100/100
I have the right stick swapped like this, what may interfere in the readings.