Apologies if this appears to be a duplicate but I cannot see a clear answer to any of the similar questions.

When trying to do a CORS request for some XML I continually get an Access is denied JS error from IE8.

My code is adapted from this example:

// Create the XHR object.

function createCORSRequest(method, url) {

  var xhr = new XMLHttpRequest();

  if (withCredentials in xhr) {

    // XHR for Chrome/Firefox/Opera/Safari.

    xhr.open(method, url, true);

  } else if (typeof XDomainRequest != undefined) {

    // XDomainRequest for IE.

    xhr = new XDomainRequest();

    xhr.open(method, url);

  } else {

    // CORS not supported.

    xhr = null;

  }

  return xhr;

}



// Helper method to parse the title tag from the response.

function getTitle(text) {

  return text.match('<title>(.*)?</title>')[1];

}



// Make the actual CORS request.

function makeCorsRequest() {

  // All HTML5 Rocks properties support CORS.

  var url = 'http://updates.html5rocks.com';



  var xhr = createCORSRequest('GET', url);

  if (!xhr) {

    alert('CORS not supported');

    return;

  }



  // Response handlers.

  xhr.onload = function() {

    var text = xhr.responseText;

    var title = getTitle(text);

    alert('Response from CORS request to ' + url + ': ' + title);

  };



  xhr.onerror = function() {

    alert('Woops, there was an error making the request.');

  };



  xhr.send();

}

from http://www.html5rocks.com/en/tutorials/cors/

This should work in IE8 using XDomainRequest, and when I load the example page and click Run sample on the html5rocks page, it works in IE8. However, as soon as I copy the code to my own page and run, I get the Access is denied error on the xhr.open() line inside XDomainRequest.

This one has me really baffled - the server is definitely set up correctly so it's something to do with the frontend. Thanks in advance to anyone who can help!