Question

JSON

{
    "AA1 1AA":{
        "ExchangeCode":"XXX",
        "ExchangeName":"XXXXX",
        "Options":{
            "10":{
                "Preference":"Preference 1",
                "Option 1":123,
                "Option 2":1234,
                "Option 3":1234,
                "Option 4":1234
            },
            "20":{ .........

            }
        }
    }
}

AA1 1AA是一个邮政编码，因此每次请求都会更改。

的jQuery

// var count = 0; is declared in document ready function so that it's global

// JSON response from server is stored in 'data'

 var key, count = 0;
 for (key in data.Options) {
     if(data.Options.hasOwnProperty(key)) {
         count++;
     }
 }

结果只是undefined

Answer 1

您似乎想要获得第一个元素。你可以这样做：

 var count = 0;
 for (var k in data) { // only simple cross browser way to get the first property
     var obj = data[k];
     for (var key in obj) {
         count++;
     }
     break; // no need to go further, we have counted in "AA1 1AA" 
 }

请注意，我删除了hasOwnProperty检查：对于JSON解析数据，它完全没用。

请注意，现代浏览器还有其他功能，例如Object.keys

计算父JSON对象内的对象

1 个答案: