JSON data format (nested)

var json = {
"key1":"value1",
"key2":{"firstname":"张","lastname":"三丰","age":100},
"key3":[
{"name":"小双","age":28,"addr":"扬州"},
{"name":"建宁","age":18,"addr":"紫禁城"},
{"name":"阿珂","age":10,"addr":"山西"},
]
};

alert(json.key2.lastname);

alert(json.key3[2].name);