PHP Treeview with Three state checkbox

[nazgul14]

I've used the code for treeview that given in DD and i add checkbox for parent,child and subchild.The problem is now that i want to do a three state checkbox,means that if i check subchild, child and parent will auto checked.Hope you guys can help me.:):)

This is a screenshot of my treeview

http://img339.imageshack.us/img339/5209/tree.gif