JSON的概念
概念： JavaScript Object Notation JacaScript对象表示法
json现在多用于存储和交换文本信息的语法
进行数据的传输
JSON 比 XML 更小 更快 ，更易解析
语法定义：
1.基本规则
数据在名称/值对中：json数据是由键值对构成的
键用引号（单双都行）引起来，也可以不使用引号
值得取值类型：
1. 数字（整数或浮点数）
2. 字符串（在双引号中）
3. 逻辑值（true 或 false）
4. 数组（在方括号中） {"persons":[{},{}]}
5. 对象（在花括号中） {"address":{"province"："陕西"....}}
6. null
数据由逗号分隔：多个键值对由逗号分隔
花括号容纳对象：使用 { } 定义json格式
方括号容纳数组：[ ]
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="js/jquery-3.3.1.min.js"></script>
<script>
//定义方法
function fun() {
//1.定义基本格式
let person = {"name":"张三",age:23,'gender':true};
//alert(person);
//2.嵌套格式 {}---> []
let persons = {
"persons":[
{"name":"张三","age":23,"gender":true},
{"name":"李四","age":21,"gender":false},
{"name":"王五","age":22,"gender":true}
]
};
//alert(persons)
//3.嵌套格式 []---> {}
let ps = [
{"name":"张三","age":23,"gender":true},
{"name":"李四","age":21,"gender":false},
{"name":"王五","age":25,"gender":true}
];
}
</script>
</head>
<body>
</body>
</html>
2.获取数据
1.json对象.键名
2.json对象[ " 键名 " ]
3.数组对象[ 索引 ]
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="js/jquery-3.3.1.min.js"></script>
<script>
//定义方法
function fun() {
//1.定义基本格式
let person = {"name":"张三",age:23,'gender':true};
//获取name的值
//let name = person.name;
let name = person["name"];
// alert(name);
//alert(person);
//2.嵌套格式 {}---> []
let persons = {
"persons":[
{"name":"张三","age":23,"gender":true},
{"name":"李四","age":21,"gender":false},
{"name":"王五","age":22,"gender":true}
]
};
//获取王五值
let name1 = persons.persons[2].name;
//alert(name1);
//alert(persons)
//3.嵌套格式 []---> {}
let ps = [
{"name":"张三","age":23,"gender":true},
{"name":"李四","age":21,"gender":false},
{"name":"王五","age":25,"gender":true}
];
//alert(ps);
//获取李四值
alert(ps[1].name);
}
</script>
</head>
<body>
</body>
</html>
JSON遍历数据
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="js/jquery-3.3.1.min.js"></script>
<script>
//定义方法
function fun() {
//1.定义基本格式
let person = {"name":"张三",age:23,'gender':true};
// 数组格式
let ps = [
{"name":"张三","age":23,"gender":true},
{"name":"李四","age":21,"gender":false},
{"name":"王五","age":25,"gender":true}
];
//获取person对象中所有的键和值
//for in 循环
// for (let key in person){
// alert(key + ":" + person[key]);
// }
//获取ps中的所有值
for (let i = 0; i < ps.length; i++) {
let p = ps[i];
for (let key in p) {
alert(key + ":" + p[key]);
}
}
}
</script>
</head>
<body>
</body>
</html>
标签：定义,gender,age,语法,person,JSON,let,true,name From： https://www.cnblogs.com/qihaokuan/p/17100757.html