{ "firstName":"John" , "lastName":"Doe" } 

firstName = "John"
lastName = "Doe"

{ 
"employees": [ 
{ "firstName":"John" , "lastName":"Doe" }, 
{ "firstName":"Anna" , "lastName":"Smith" }, 
{ "firstName":"Peter" , "lastName":"Jones" } 
] 
} 

  $.ajax({
    type: 'POST',
    url: '../../caseHandler.ashx?action=GetCase&id=' + id.toString(), //url action是方法的名称
    data: "",
    dataType: "text", //可以是text，如果用text，返回的结果为字符串；如果需要json格式的，可以设置为json
    ContentType: "application/json; charset=utf-8",
    success: function (returnedData) {
      getMarkerFeature(eval("(" + returnedData+ ")"));
    },
    error: function (msg) {
      alert("访问失败："+ msg);
    }
  });

var employees = [
{ "firstName":"Bill" , "lastName":"Gates" },
{ "firstName":"George" , "lastName":"Bush" },
{ "firstName":"Thomas" , "lastName": "Carter" }
];

var employees = [
{ "firstName":"Bill" , "lastName":"Gates" },
{ "firstName":"George" , "lastName":"Bush" },
{ "firstName":"Thomas" , "lastName": "Carter" }
];
alert(employees[0].lastName); // 方式一
alert(employees[0]["lastName"]); // 方式二