Mouse object from manual :
1- Set cursor style
Set the type of mouse cursor showing for the canvas in the HTML page. The cursor can be hidden completely by choosing None.
2- Set cursor from sprite
Set the cursor image from a Sprite object. This is preferable to setting a sprite to the mouse co-ordinates, because the input lag is significantly lower. Various limitations apply: the sprite image is used as it appears in the image editor, not taking in to account size or rotation in the layout; the image cannot be too large (64x64 is usually the limit); and support varies depending on browser and OS.