25.javascript json

1.JSON格式大致是如下样子

大括号包裹数据，数据已键值对形式存在，键需要用引号，接着使用冒号:，再接着就是其值。

多个键值对用逗号隔开。

{
"employees":[
    {"firstName":"Bill", "lastName":"Gates"}, 
    {"firstName":"Steve", "lastName":"Jobs"},
    {"firstName":"Alan", "lastName":"Turing"}
]
}

{"firstName":"Bill", "lastName":"Gates"} 

2.字符串格式的JSON数据转换成JSON请使用JSON.parse(text);

var text = '{ "employees" : [' +
'{ "firstName":"Bill" , "lastName":"Gates" },' +
'{ "firstName":"Steve" , "lastName":"Jobs" },' +
'{ "firstName":"Alan" , "lastName":"Turing" } ]}';

var obj = JSON.parse(text);　

3.调用json数据：

<p id="demo"></p>

<script>
document.getElementById("demo").innerHTML =
obj.employees[1].firstName + " " + obj.employees[1].lastName;
</script> 

4.将JSON数据转换成字符串JSON.stringify(obj);

var obj = {"name":"Bill", "age":62, "city":"Seatle"};
var myJSON = JSON.stringify(obj);
document.getElementById("demo").innerHTML = myJSON;