javascript - obj的长度是1 - javascript

Question

我正在尝试根据用户插入的邮政编码自动填充城市和州值。我无法将输入的邮政编码与 json 对象中可用的邮政编码进行比较。 obj length 的值为 1 ，必须为 3。

var text = '{"zipcodes":[' +
'{"zip":"22031","city":"Fairfax" ,"State":"VA" },' +
'{"zip":"22032","city":"AshBurn" ,"State":"VA" },' +
'{"zip":"22033","city":"Tysons" ,"State":"VA" }]}';

var obj = JSON.parse(text);
var n = Object.keys(obj).length;

for(i=0; i<=n; i++){

    if(obj.zipcodes[i].zip.parseInt() == zipcodes.parseInt()){

        document.getElementById("city").value = obj.zipcodes[i].city;
        document.getElementById("state").value = obj.zipcodes[i].State;

    }
}

Answer 1

解析后的对象变为:

{
  "zipcodes":[
    {"zip":"22031","city":"Fairfax" ,"State":"VA" },
    {"zip":"22032","city":"AshBurn" ,"State":"VA" },
    {"zip":"22033","city":"Tysons" ,"State":"VA" }]}
  ]
};

所以对象的键数是 1，即邮政编码。如果您想要邮政编码的数量，

使用这个:

var obj = JSON.parse(text);
var n = obj.zipcodes.length;