Question

我的任务是让小测验应用程序正常工作。我将问题保存为private static void SetTimer(SocketUser user) { var account = UserAccounts.GetAccount(user); account.TimerOn = true; timer = new System.Timers.Timer(1000); //(1000 * 60) * 10 timer.Elapsed += OnTimedEvent; timer.Enabled = true; timer.AutoReset = false; } private static void OnTimedEvent(Object source, ElapsedEventArgs e) { Console.WriteLine("Timer ended {0}", e.SignalTime); }文件并执行json请求。当我初始化运行http个问题时，它会呈现给浏览器。

JSON.parse()

但是，当我重构它以进行var output = document.getElementById('output'); // this allows us to keep it as a global value var myObj = ''; loadQuestions(); console.log(myObj); // var myQuestions = '[{"question":"What is your nearest star?","answers":{"a":"Alpha Centauri","b":"Barnard\'s Star","c":"Sirius","d":"Sol"},"correctAnswer":"d"},{"question":"What color is grass?","answers":{"a":"Blue","b":"Red","c":"Green","d":"Purple"},"correctAnswer":"c"}]'; // var myObj = JSON.parse(myQuestions); // for (var i in myObj) { // output.innerHTML += myObj[i].question + '? <br>'; // }调用时，它会在控制台中迭代，但不会在浏览器窗口中迭代：

AJAX

我认为它可能是我的var output = document.getElementById('output'); // this allows us to keep it as a global value var myObj = ''; loadQuestions(); console.log(myObj); function loadQuestions() { // http request // this will allow you to pull in // the questions from the api that // your questions or data is stored in var a = new XMLHttpRequest(); a.open("GET", "https://api.myjson.com/bins/8xmud", true); // opened request with address with a.onreadystatechange = function(){ if (a.readyState == 1) { var myQuestions = JSON.parse(a.responseText); console.log(myQuestions); for (var i in myQuestions) { output.innerHTML = myQuestions[i].question + '? <br>'; } } console.log(a); } a.send(); }循环，但这是正确的。我不清楚为什么，尽管得到for...in或Status: OK，它并没有像以前一样在浏览器窗口中迭代。

Answer 1

var output = document.getElementById('output');
// this allows us to keep it as a global value
var myObj = '';
loadQuestions();
console.log(myObj);

function loadQuestions() {
  // http request
  // this will allow you to pull in
  // the questions from the api that
  // your questions or data is stored in
  var a = new XMLHttpRequest();
  a.open("GET", "https://api.myjson.com/bins/8xmud", true); // opened request with address with
  a.onreadystatechange = function(){
    if (a.readyState == 4) {
      var myQuestions = JSON.parse(a.responseText);
      console.log(myQuestions);
      for (var i in myQuestions) {
        output.innerHTML += myQuestions[i].question + '? <br>';
      }
    }
    console.log(a);
  }
  a.send();
}

<div id ="output"></div>

AJAX：问题无法呈现给浏览器

1 个答案: