function chg_sub_option(sObj,t){
    var v = sObj.value;
    var obj    = document.getElementById(t);
    if(!v || !sub_city_arr[v]){
        obj.length = 0;
        add_opt(t,'没有数据',0);
        obj.options[0].selected=true;
        return false;
    }
    if(sub_city_arr[v].length){
        obj.length =0;
        for(manuid in sub_city_arr[v]){
            add_opt(t,sub_city_arr[v][manuid],manuid);
        }
        obj.options[0].selected=true;
    }
}

function add_opt(obj,text,value){
    s_obj = document.getElementById(obj);
    Opt_len = s_obj.length;
    newOpt = document.createElement("OPTION");
    newOpt.text = text;
    newOpt.value = value;
    app = navigator.appName;
    if(app.indexOf("Microsoft")!=-1){
        s_obj.add(newOpt);
    }else{
        s_obj.add(newOpt,s_obj.options[Opt_len+1]);
    }
}