[рони]

mrmammoth,

var  a1 = {
                param1: "value1",
                param2: "value2"

            };
            a1["param3"] = {
                'subparam1': "vol1",
                'subparam2': "vol2"

            };
            a1["param3"]['subparam3']= "vol3"
            alert(a1.param3.subparam3);