var aa = [1,21,21,21,28];
var bb = [3,4,27,39,21];
var cc = [];
var tmp = aa.concat(bb);
var o = {};
for (var i = 0; i < tmp.length; i ++){
(tmp[i] in o) ? o[tmp[i]] ++ : o[tmp[i]] = 1;
}
for (x in o){
if (o[x] == 1){
cc.push(x);
}
}
alert(cc); //这里可以查出cc为1,3,4,27,28,39
下面该如何写出这些cc值在aa数组或bb数组中对应的索引值呢???