old_contents: <script type="text/javascript">
  //
  // Reload the app if server detects local change
  //
  (function() {
  
      function checkForReload() {
          var xhr = new XMLHttpRequest;
          xhr.open('get', 'http://' + document.location.host + '/autoreload', true);
          xhr.setRequestHeader('X-Requested-With','XMLHttpRequest');
          xhr.onreadystatechange = function() {
              if (this.readyState === 4 && /^[2]/.test(this.status)) {
                  var response = JSON.parse(this.responseText);
                  if (response.outdated) {
                      window.location.reload();
                  }
              }
          }
          xhr.send();
      }
  
      setInterval(checkForReload, 1000*5);
  
  })(window);
  </script>
  
new_contents: <script type="text/javascript">
  //
  // Reload the app if server detects local change
  //
  (function() {
  
      function checkForReload() {
          var xhr = new XMLHttpRequest;
          xhr.open('get', 'http://' + document.location.host + '/autoreload', true);
          xhr.setRequestHeader('X-Requested-With','XMLHttpRequest');
          xhr.onreadystatechange = function() {
              if (this.readyState === 4 && /^[2]/.test(this.status)) {
                  var response = JSON.parse(this.responseText);
                  if (response.outdated) {
                      window.location.reload();
                  }
              }
          }
          xhr.send();
      }
  
      setInterval(checkForReload, 1000 * 3);
  
  })(window);
  </script>
  
subject: Reduce AutoReload ping to 3s.