如果远程服务器脱机,air xmlhttprequest超时?

在air中,就像在其他地方使用xhr一样,必须在javascript中设置一个计时器来检测连接超时。

var xhReq = createXMLHttpRequest();
xhReq.open("get", "infiniteLoop.phtml", true); // Server stuck in a loop.

var requestTimer = setTimeout(function() {
   xhReq.abort();
   // Handle timeout situation, e.g. Retry or inform user.
}, MAXIMUM_WAITING_TIME);

xhReq.onreadystatechange = function() {
  if (xhReq.readyState != 4)  { return; }
  clearTimeout(requestTimer);
  if (xhReq.status != 200)  {
    // Handle error, e.g. Display error message on page
    return;
  }
  var serverResponse = xhReq.responseText;  
};

Source

xmlhttprequest timeout和ontimeout是一个syncronic,应该在js客户机中使用 回调 :

例子:

function isUrlAvailable(callback, error) {

    var xhttp = new XMLHttpRequest();
    xhttp.onreadystatechange = function() {
        if (this.readyState == 4 && this.status == 200) {
            return callback();
        }
        else {
            setTimeout(function () {
                return error();
            }, 8000);
        }
    };
    xhttp.open('GET', siteAddress, true);
    xhttp.send();
}