javascript 处置 json _JavaScript

javascript 处理 json

1. 什么是JSON。JSON （JavaScript Object Notation）一种简单的数据格式，比xml更轻巧。 JSON 是 JavaScript 原生格式，这意味着在 JavaScript 中处理 JSON 数据不需要任何特殊的 API 或工具包。

?{ "people": [?

? { "firstName": "Brett", "lastName":"McLaughlin", "email": "brett@newInstance.com" },?

? { "firstName": "Jason", "lastName":"Hunter", "email": "jason@servlets.com" },?

? { "firstName": "Elliotte", "lastName":"Harold", "email": "elharo@macfaq.com" }?

?]}?

语义说明（个人总结，不完全正确）：

1。对象用｛｝表示，

2。键值对之间用：割开，键或值用双引号引起来。

3。数组用［］表示

4。多个键值对之间用逗号 ,分开。

以下代码绝大多数来自于：?主题：JSON学习：?http://www.iteye.com/topic/71343，放到这里只是为了总结，如有侵犯原作版权，请联系本博主。［本文以下部分版权归原作所有］

js 读取 json

function showJSON() {   
    var user =    
    {    
        "username":"andy",   
        "age":20,   
        "info": { "tel": "123456", "cellphone": "98765"},   
        "address":   
            [   
                {"city":"beijing","postcode":"222333"},   
                {"city":"newyork","postcode":"555666"}   
            ]   
    }   
       
    alert(user.username);   
    alert(user.age);   
    alert(user.info.cellphone);   
    alert(user.address[0].city);   
    alert(user.address[0].postcode);   
}

2。 js 修改 JSON

function showJSON() {   
    var user =    
    {    
        "username":"andy",   
        "age":20,   
        "info": { "tel": "123456", "cellphone": "98765"},   
        "address":   
            [   
                {"city":"beijing","postcode":"222333"},   
                {"city":"newyork","postcode":"555666"}   
            ]   
    }   
       
    alert(user.username);   
    alert(user.age);   
    alert(user.info.cellphone);   
    alert(user.address[0].city);   
    alert(user.address[0].postcode);   
       
    user.username = "Tom";   
    alert(user.username);   
}

??JSON提供了json.js包，下载http://www.json.org/json.js?后，将其引入然后就可以简单的使用object.toJSONString()转换成JSON数据。

function showCar() {   
    var carr = new Car("Dodge", "Coronet R/T", 1968, "yellow");   
    alert(carr.toJSONString());   
}   
  
function Car(make, model, year, color)       {   
     this.make  =  make;   
     this.model  =  model;   
     this.year  =  year;   
     this.color  =  color;   
}

可以使用eval来转换JSON字符到Object

function myEval() {   
    var str = '{ "name": "Violet", "occupation": "character" }';   
    var obj = eval('(' + str + ')');   
    alert(obj.toJSONString());   
}

或者使用parseJSON()方法

function myEval() {   
    var str = '{ "name": "Violet", "occupation": "character" }';   
    var obj = str.parseJSON();   
    alert(obj.toJSONString());   
}

js 中数组引用

?var people =?

? { "programmers": [?

? ? { "firstName": "Brett", "lastName":"McLaughlin", "email": "brett@newInstance.com" },?

? ? { "firstName": "Jason", "lastName":"Hunter", "email": "jason@servlets.com" },?

? ? { "firstName": "Elliotte", "lastName":"Harold", "email": "elharo@macfaq.com" }?

?? ],?

? "authors": [?

? ? { "firstName": "Isaac", "lastName": "Asimov", "genre": "science fiction" },?

? ? { "firstName": "Tad", "lastName": "Williams", "genre": "fantasy" },?

? ? { "firstName": "Frank", "lastName": "Peretti", "genre": "christian fiction" }?

?? ],?

? "musicians": [?

? ? { "firstName": "Eric", "lastName": "Clapton", "instrument": "guitar" },?

? ? { "firstName": "Sergei", "lastName": "Rachmaninoff", "instrument": "piano" }?

?? ]?

? }?

 people.programmers[0].lastName;

参考：

http://www.iteye.com/topic/71343?

掌握 Ajax，第 10 部分: 使用 JSON 进行数据传输（IBM）