mouse move programatically

I'm making custom combobox. So, when items drops down I would like to programticaly move mouse cursor to first item in dropdown part of combo box. Can this be done ?

First off, i dont think you can control mouse cursor movement with a browser, as that would allow some evil web developer to lock your mouse in a spot.

Secondly, a lot of people would probably be annoyed by the effect of their mouse cursor jumping to a position automatically. Well maybe not annoyed as much as confused, especially if they are not very computer savvy :)