title: XmlHttpRequest onprogress interval
body: <p>I'm using XmlHttpRequests to upload images to a server and I'd like to show the user the progress of these uploads.</p>
  
  <p>Unfortunately the interval between calls to my onprogress-event handler is too large. Usually onprogress is called only once or twice for a 500k image.</p>
  
  <p>Here is my code:</p>
  
  <pre><code>/* This function is not called often enough */
  function progress(e){
      console.log('Uploading: ' + Math.round((e.loaded / e.total) * 100) + ' %');
  }
  
  var xhr = new XMLHttpRequest();
  xhr.upload.addEventListener('progress', progress, false);
  xhr.send(data);
  </code></pre>
  
  <p>Can this behaviour be changed or is this hardcoded somewhere in the browser implementation?</p>