Question

我的请求有以下代码：

     var req = new XMLHttpRequest();
  req.onreadystatechange = function() {
    if (req.readyState == 4)       // state of 4 is 'done'. The request has completed
    {
     callback(req.responseText); // The .responseText property of the request object
    } else {                       // contains the Text returned from the request.
      console.log(req.readyState);
    }
  };
  req.open("GET", url, true);
  req.send();

然而，readyState正在变为1并且正确触发（我看到它在控制台中回显）但它只是没有进展到2.经过一段时间它超时并且我得到了控制台：

无法加载资源：net :: ERR_CONNECTION_TIMED_OUT

未捕获的SyntaxError：意外的输入结束

任何人都知道为什么会这样？

Answer 1

把这个

req.open("GET", url, true);
  req.send();

在这一行之上

  req.onreadystatechange = function() {

Answer 2

很抱歉，这最终成为VPN问题，而不是脚本问题。

Answer 3

function getLatestfileinAllPath(urls)?
{
    for(i = 0;i<urls.length;i++){
        run(i)
    }
    function run(){
        var request = new XMLHttpRequest();
        request.open('POST', url[i]);
        request.send(JSON.stringify({"data":"some data"}));
        request.onreadystatechange = function()
        {
            if (request.readyState  === XMLHttpRequest.DONE  && request.status == 200)
            {
                console.log(JSON.parse(request.response));
            }
         }
        }; 
    }
}

onreadystatechange只触发一次

3 个答案: