XmlHttpRequest.onload无法在Edge浏览器中运行

Question

I'm running into an issue where Microsoft Edge browser isn't able to execute XmlHttpRequest.onload . But it does execute in Chrome, Firefox, and Safari.

I'm creating an XmlHttpRequest object:

var xhr = new XMLHttpRequest();
xhr.responseType = "json";
xhr.open("POST", authenticateUrl, true);
xhr.setRequestHeader("X-OpenAM-Username", email);
xhr.setRequestHeader("X-OpenAM-Password", password);
xhr.setRequestHeader("Content-Type", "application/json");

alert("XHR object is created"); 

xhr.onload = function () {
  alert("start onload...");

  //...receives response from service...
}

xhr.send();

The alerts in place to validate it's reaching a specific line of code. After the XMLHttpRequest object is created, the code goes into the onload function. Microsoft Edge won't go into it. As I said, Chrome, Firefox, and Safari execute this code fine.

Is there something additional needed for making Microsoft Edge run this code?

Answer 1

The onload function shouldn't be called until you send the XHR and the response comes back (unless there is an error). Are you calling xhr.send()?

https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequestEventTarget/onload

Answer 2

Place the xhr.responseType = "json" line after the xhr.open(...)

Because the xhr.responseType is not allowed for synchronous requests which is determined by the third parameter in the open() call.

Wait, that was in IE11, i've tried your snippet in Edge and it ran just fine.

Try adding a

xhr.onerror = err => alert('Error:' + err.message);

to see if an error occurred.