[dandelany]

I don't think the browser is technically able to move the mouse cursor, I imagine that happens at the OS level. Anyone have a counterexample?

[icebraining]

The OS has APIs that applications like the browser can use for that, e.g.:

Win32: http://msdn.microsoft.com/en-us/library/windows/desktop/ms64...

X11: http://tronche.com/gui/x/xlib/input/XWarpPointer.html

[repsilat]

Applications in most operating systems can set the cursor position. Full-screen games often reset it to the middle of the screen every frame.

IIRC it isn't exposed to JS except maybe for some new fullscreen API (not my area, sorry.)