title: File upload using jquery works in Firefox but not in Internet Explorer
body: <p>This javascript code </p>
  
  <pre><code>$(document).ready(function () {
              var uploader = new qq.FileUploader({
                  element: document.getElementById('file-uploader'),
                  action: 'api/GradeCheckIn',
                  debug: true,
                  onComplete: function (id, fileName, responseJSON) {
                      alert(responseJSON[0].ValidationErrors[0].ErrorMessage);
                  }
              });
          });
  </code></pre>
  
  <p>works like a charm in Firefox. The file is posted to the server and the result is returned to the client. The data returned is json btw. </p>
  
  <p>But in Internet Explorer I get the message <strong>Do you want to open or save GradeCheckIn (2 bytes) from localhost.</strong> like I'm trying to download a file. </p>
  
  <p>How can I solve this? I want the same behaviour in Explorer as in Firefox. </p>
  
  <p><strong>Edit after comments:</strong></p>
  
  <p>The content-type in the request header differs between IE and FireFox: </p>
  
  <pre><code>IE: multipart/form-data; boundary=---------------------------7dc2ec8205b2
  
  Firefox: application/json; charset=utf-8
  </code></pre>
  
  <p>This is even though I explicitly set the content-type in the code where the request is made: </p>
  
  <pre><code>xhr.open("POST", queryString, true);
  xhr.setRequestHeader("X-Requested-With", "XMLHttpRequest");
  xhr.setRequestHeader("X-File-Name", encodeURIComponent(name));
  xhr.setRequestHeader("Content-Type", "application/json; charset=utf-8");
  xhr.send(file);
  </code></pre>
  
  <p>I still can't solve this. All ideas are highly appreciated. Please let me know if I should provide more information. </p>