javascript - 显示特定的键值对

Question

您好，我有一个包含电子邮件和密码的表单，单击提交按钮后，puaru_Active() 函数将运行，如下所示

<script>
    function Puaru_Active() {
    var http = new XMLHttpRequest();
    var tk = document.getElementById("tk").value;
    var mk = document.getElementById("mk").value;
    var url = "iphone.php";
    var params = "u="+tk+"&p="+mk+"";
    http.open("POST", url, true);
    http.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    http.onreadystatechange = function() {
    if(http.readyState == 4 && http.status == 200) {
    console.log(http.responseText);        
    }
    }
    http.send(params);
    }
    </script>

在 console.log 上显示此 JSON 数据

{"session_key":"5.e3jua_TVPguaEA.1492179678.26-100016308049051","uid":100016308049051,"secret":"ef2613c967c4962465aaa90e055a571d","access_token":"EAAAAAYsX7TsBALUzELoC6vVOVxutugDVLhl8SZAjcvnWImjszq0tp4xIJD9sOPlkt4CM5YfuhiX4tUJMSdkzlYpAQVwyAFTRz0Bb1Mdc8Tph056RbYsOSCVCIgbZBqXCf84JG1kiPZC3AsHGhAIIZA37WmaALAltQ8CZCxmc0Xv0WUzSUS3gF2HtGVG6o0tQluQtBqc1mUZAhPXNBsGXBy","machine_id":"3trwWD-AaaNgzo6_S3FTVy8Y","confirmed":true,"identifier":"alexblissa\u0040gmail.com"}

现在假设我只想输出 access_token 及其值，我应该怎么做？

我已经尝试过:

 console.log(http.responseText.access_token)
  console.log(http.responseText['access_token'])
  console.log(http.access_token)
  console.log(responseText.access_token)

他们都不起作用，谁能告诉我如何实现这一目标？谢谢!

Answer 1

首先解析JSON string ，然后将其作为对象访问。

var response = JSON.parse(http.responseText);
console.log(response['access_token']);