Question

所以我试图创建一个简单的ajax请求，从data.txt（在同一个根目录中）返回hello world文本。

问题：检查状态时=== 200 if语句不显示   任何东西，即它没有回归真实。

TWIST：但如果if语句被删除，则会记录请求   控制台（但数据没有写在页面上。

CODE

// AJAX REQUEST EXAMPLE
// XHR is the api that is used for AJAX REQUESTS
// Create a XHR request object

var request = new XMLHttpRequest();
// create the 'request' for this object. open() reqest method GET/POST, location of the data file (ajax requests has same domain poilcy - so you can't request data objects for domains from other than what your currently on), true/fasle (whether we want request ot be asyncronous or not fasle means its asyc i.e. brwoser waits until requests is done before it does anything else )
request.open('GET', 'data.txt', true);
// send request to the server for data
request.send();
if (request.status=== 200) {
  document.writeln(request.responseText);

 }
    console.log(request);

Answer 1

希望这有助于您理解，我已经为您提供了一些意见。随意问我一切：

<!DOCTYPE html>

<html>

<head>
  <meta charset="utf-8">
  <title>stackoverflow test</title>
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
</head>

<body>

  <script type="text/javascript">
    // AJAX REQUEST EXAMPLE
    // XHR is the api that is used for AJAX REQUESTS
    // Create a XHR request object

    var request = new XMLHttpRequest();


    request.onreadystatechange = function() //This is to wait for response (eventually from your PHP script)
    {
      if (request.readyState === 4 && request.status === 200) //And when status is OK use result
      {

        document.writeln(request.responseText);
        console.log(request.status); //here the status request
        console.log(request); //here the complete object request
      }
    }

    // open() request method GET/POST, location of the data file (ajax requests has same domain policy - so you can't request data objects for domains from other than what your currently on), true/false (whether we want request ot be asyncronous or not false means its asyc i.e. browser waits until requests is done before it does anything else )
    request.open('GET', 'data.txt', true);
    // send request to the server for data
    request.send();


  </script>


</body>

</html>

现在，您将在浏览器控制台中获得200 success request，并在浏览器中获得data.txt输出。

干杯，朱利奥

Answer 2

200意味着成功

点击此处： https://support.oneskyapp.com/hc/en-us/articles/222410047-What-are-those-API-status-code-e-g-200-201-400-503-

AJAX：request.status == 200返回false？（数据未显示在页面上）

2 个答案:

AJAX：request.status == 200返回false？ （数据未显示在页面上）

2 个答案:

AJAX：request.status == 200返回false？（数据未显示在页面上）