var URL = 'http://localhost/Orthanc/instances';  // Pay attention to same-origin policy
var USERNAME = 'alice';
var PASSWORD = 'alicePassword';

$(document).ready(function() {
  $('#upload').click(function() {

    var f = document.getElementById('dicom').files;

    if (f.length === 0) {
      alert('No DICOM file selected');
    }
    else {
      var reader = new FileReader();

      reader.onload = function() {

        // https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/readyState
        if (this.readyState === 2 /* HEADERS_RECEIVED */) {
          var dicom = reader.result;

          // https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/Sending_and_Receiving_Binary_Data#Sending_binary_data
          var xhr = new XMLHttpRequest();
          xhr.onload = function(event) {
            if (xhr.readyState === 4 /* DONE */) {
              if (xhr.status == 200) {
                alert('Success!');
              } else {
                alert('Failure');
              }
            }
          }
          
          xhr.open('POST', URL, true);
          xhr.setRequestHeader('Authorization', 'Basic ' + btoa(USERNAME + ':' + PASSWORD));
          xhr.send(new Uint8Array(dicom));
        };
      }

      reader.readAsArrayBuffer(f[0]);
    }
  });
});