I have gone through many scripts of linked listboxes (which have category -> sub category relation). but i need one in which i can also set parent and child options which are selected by default.

also i may have several instances of the same cat->subcat listboxes on the same page so the script should have only one cat->subact array which is shared among all the instances and i should be able to set the defaults of all the listboxes separately..

it woud be extremely helpful if anyone lets me know of such a script or any other solution