如何随机选择对象密钥？

我有以下代码；

namedarray['India']='New Delhi';
namedarray['Australia']='Canberra';
namedarray['Indonasia']='Jakarta';
namedarray['Iran']='Tehrani';
namedarray['Iraq']='Bhagdad';
namedarray['Nijeria']='Abuja';

document.getElementById('question').innerHTML="Q." +namedarray['Nepal']+"  is capital for which country";

我想代替尼泊尔，从对象中随机选择一个密钥。我怎样才能做到这一点？

尝试这个：

function fetch_random(obj) {
    var temp_key, keys = [];
    for(temp_key in obj) {
       if(obj.hasOwnProperty(temp_key)) {
           keys.push(temp_key);
       }
    }
    return obj[keys[Math.floor(Math.random() * keys.length)]];
}

var random_name = fetch_random(namedarray);
document.getElementById('question').innerHTML="Q." + random_name +"  is capital for which country"