Question

var USER_DETAILS= {
    "details": [
        {
            "name": "john",
            "passwd": "xyz",
            "email": "j@g.com",
            "contact": "87685778",
            "lastLogin": "Sun Aug 24 2014 23:30:54 GMT+0530 (India Standard Time)"
        }, 
        {
            "name": "peter",
            "passwd": "xyz",
            "email": "p@g.com",
            "contact": "09820984",
            "lastLogin": "Sun Aug 24 2014 23:41:04 GMT+0530 (India Standard Time)"
        }, 
        {
            "name": "s",
            "passwd": "123",
            "email": "s@g.com",
            "contact": "3435",
            "lastLogin": "Mon Aug 25 2014 00:05:45 GMT+0530 (India Standard Time)"
        }, 
        {
            "name": "y",
            "passwd": "k",
            "email": "j@jhj.com",
            "contact": "87685778",
            "lastLogin": "Mon Aug 25 2014 00:12:59 GMT+0530 (India Standard Time)"
        }, 
        {
            "name": "johny",
            "passwd": "234",
            "email": "lkj@g.com",
            "contact": "34543",
            "lastLogin": "Mon Aug 25 2014 00:20:44 GMT+0530 (India Standard Time)"
        }
    ]
}

我现在有这个jason数据我需要访问“John”这个名字。我试过像访问它一样 USER_DETAILS.details[i].name但我收到错误USER_DETAILS.details is undefined。

以下是我访问JSON的其余代码

function check_details()
{
var users=JSON.parse(localStorage.getItem('USER_DETAILS'));
for (var key in users)
  {
  alert(users.details[0].name);
  }
}

Answer 1

尝试这样的事情：

USER_DETAILS.details[0].name

USER_DETAILS它是一个属性为details的对象，它是一个数组，而'John'位于数组的第一个实例中。

这一切在我的结尾都很合理：

var USER_DETAILS= /* your sample code */;
console.log( USER_DETAILS.details[0].name);

Answer 2

试试这个

function check_details()
{
    var users=JSON.parse(localStorage.getItem('USER_DETAILS'));
    for (var key in users.details)
    {
        alert(users.details[key].name);
    }
}

你试图遍历只有一个对象users的{{1}}，所以你需要遍历details对象以获取所有用户

jsfiddle demo (without using localStorage)

供参考，有关for...in loops

的文档

Answer 3

错误 USER_DETAILS.details未定义，因为您的JSON字符串中存在语法错误，缺少＆＃39;和＆＃39; ...

你的：= {＆＃34;详情＆＃34;：[{＆＃34; name＆＃34;：＆＃34; john＆＃34;，...
正确：=＆＃39; {＆＃34;详情＆＃34;：[＆＃39;＆＃39; {＆＃34;姓名＆＃34;：＆＃34;约翰＆＃34; ，...

这是一个有效的例子

var USER_DETAILS = '{"details":[' +
'{"name":"John","passwd":"1234", "email":"john@gmail.com" },' +

'{"name":"Anna","passwd":"5678", "email":"anna@gmail.com" },' +

'{"name":"Peter","passwd":"9945", "email":"peter@gmail.com" }]}';

obj = JSON.parse(USER_DETAILS);
document.getElementById("paragraphid").innerHTML =
obj.details[0].name + " " + obj.details[0].email;

最佳实践：

缩进并将每个实体/行的JSON字符串（+）连接到区分各个属性和值以便于阅读

如何访问此JSON中的数据？

3 个答案: