got it..
xfa.resolvenode("Form.Dropdownlist.ui.#choiceList.border.edge.color[0]").value = "123,123,123";
xfa.resolvenode("Form.Dropdownlist.ui.#choiceList.border.edge.color[1]").value = "123,123,123";
xfa.resolvenode("Form.Dropdownlist.ui.#choiceList.border.edge.color[2]").value = "123,123,123";
xfa.resolvenode("Form.Dropdownlist.ui.#choiceList.border.edge.color[3]").value = "123,123,123";