<script>
    //json对象
    var person1 = {"name":"刘川","sex":"男","age":"20多"};
    console.log(person1);//[object Object]
    console.log(person1["name"]);
    console.log(person1["sex"]);
    console.log(person1["age"]);
</script>

var person2 = {name:"某川",sex:"男",age:"20"};
person2["name"]="川某";
console.log(person2["name"]);

<script>
    //js数组，json格式
    var arr = ["立铭","锟锟","坤哥"];
    console.log(arr[0]);
    arr[0] = "小曲";
    console.log(arr[0]);
</script>

//复合练习
var classInfo = {
    "className":"Java12班",
    "stuList":["王五","赵六","钱七"]
};
//需求：想获取班级名
console.log(classInfo["className"]);
//需求：想将学生列表中，最后追加一个张三
classInfo["stuList"].push("张三");
console.log(classInfo);
//需求：遍历学生列表
var stuList = classInfo["stuList"];
for (x in stuList){
    console.log(stuList[x]);
}

<script>
    var pList = [
        {pid:"001",pname:"小米",price:"10.55"},
        {pid:"007",pname:"面条",price:"2.10"},
        {pid:"009",pname:"大米",price:"5.99"}
    ];
    console.log(pList[1]["price"]);
    pList[2]["price"] = "3.99";
    console.log(pList);
</script>

<script>
    //建议使用for..in循环遍历，更简单
    //效果：001 小米 10.55
    var pList = [
        {pid:"001",pname:"小米",price:"10.55"},
        {pid:"007",pname:"面条",price:"2.10"},
        {pid:"009",pname:"大米",price:"5.99"}
    ];
    //外层循环：pList[i] 循环到某个商品对象
    for(i in pList){
        var str = "";
        //内层循环：pList[i][n] 循环的是某个商品对象的某个属性
        for (n in pList[i]){
            str+=pList[i][n]+" ";
        }
        console.log(str);
    }

    var classInfo = {
        "className":"传智专修学院Java12班",
        "stuList":["王五","赵六","钱七"]
    };
    //遍历王五、赵六、钱七
    var sList = classInfo["stuList"];
    for (i in sList) {
        console.log(sList[i]);
    }
</script>

<script>
    var p1 = '{"name":"刘川","sex":"男","age":"20"}';
    console.log(p1["name"]);//undefined
    //转换
    var person = eval("("+p1+")");
    console.log(person["name"]);//刘川
</script>