Question

我想知道如何在发送后验证xmlHttp请求的状态。我该怎么做呢？感谢。

function sendRequest(){
    //get refresh access token   
    var accessToken = 'xxx';
    //get user_id
    var userid = document.getElementById('userid').value;
    //get request_token
    var requestToken = document.getElementById('requestToken').value;

     //insert database
     var xmlHttp = new XMLHttpRequest();
     var url="database.php";
     var parameters = "accessToken=" + accessToken + "&userid=" + userid + "&requestToken=" + requestToken ;
     xmlHttp.open("POST", url, true);

    //send request
     xmlHttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
     xmlHttp.setRequestHeader("Content-length", parameters.length);
     xmlHttp.setRequestHeader("Connection", "close");
     xmlHttp.send(parameters);

    //check status
    if(xmlHttp.status == Ok){
        alert('success!');
    }else {
        alert('error');
    }

}

Answer 1

我认为这就是你正在寻找的东西

var xhttp = new XMLHttpRequest();
  xhttp.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
      document.getElementById("demo").innerHTML =
      this.responseText;
    }
  };
  xhttp.open("GET", "http://your-url.com/your-page.php", true);
  xhttp.send();

Answer 2

每次onreadystatechange更改时都会触发readyState事件。

在服务器请求期间，readyState从0更改为4：

0：请求未初始化
  1：建立服务器连接   2：收到请求
  3：处理请求
  4：请求已完成且响应已准备好

因此，在您的代码中，您可以添加侦听器以检查onreadystatechange事件并检查其中的状态，如下所示 -

function sendRequest(){
    //get refresh access token   
    var accessToken = 'xxx';
    //get user_id
    var userid = document.getElementById('userid').value;
    //get request_token
    var requestToken = document.getElementById('requestToken').value;

     //insert database
     var xmlHttp = new XMLHttpRequest();
     var url="database.php";
     var parameters = "accessToken=" + accessToken + "&userid=" + userid + "&requestToken=" + requestToken ;

     //Here is the onreadystatechange event listener.
     xmlHttp.onreadystatechange = function() {
         if (this.readyState == 4 && this.status == 200) {
             alert('success');
         } else if(this.readyState == 4 && this.status != 200) { 
             alert('error');
         }
     };
     xmlHttp.open("POST", url, true);

    //send request
     xmlHttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
     xmlHttp.setRequestHeader("Content-length", parameters.length);
     xmlHttp.setRequestHeader("Connection", "close");
     xmlHttp.send(parameters);

    //check status
    if(xmlHttp.status == Ok){
        alert('success!');
    }else {
        alert('error');
    }

}

Answer 3

<!DOCTYPE html>
<html>
<body>

<h2>Using the XMLHttpRequest object</h2>

<button type="button" onclick="loadXMLDoc()">Change Content</button>

<p id="test"></p>

<script>


function sendRequest(){
    //get refresh access token   
    var accessToken = 'xxx';
    //get user_id
    var userid = document.getElementById('userid').value;
    //get request_token
    var requestToken = document.getElementById('requestToken').value;


    var xmlHttp = new XMLHttpRequest();
    var xhttp = new XMLHttpRequest();
    xmlHttp.onreadystatechange = function() {
      if (this.readyState == 4 && this.status == 200) {
        document.getElementById("test").innerHTML =
        this.responseText;
      }
    };
    //insert database
     var url="database.php";
     var parameters = "accessToken=" + accessToken + "&userid=" + userid + "&requestToken=" + requestToken ;
     xmlHttp.open("POST", url, true);

    //send request
     xmlHttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
     xmlHttp.setRequestHeader("Content-length", parameters.length);
     xmlHttp.setRequestHeader("Connection", "close");
     xmlHttp.send(parameters);



}

</script>

</body>
</html>

如何返回xmlHttp请求状态？

3 个答案: