A joystick includes a first structural component, a second structural component, a light emitter, an optical sensor and a processor. The second structural component is assembled with the first structural component to form a chamber. The light emitter is disposed inside the chamber for illuminating one surface of the second structural component. The optical sensor is disposed inside the chamber for capturing the illuminated surface of the second structural component. The processor is electrically connected to the optical sensor and adapted to analyze an intensity distribution of the illuminated surface for determining if the joystick is obliquely pressed or laterally shifted in a relative manner.