reload.js

function refreshOnChanges(checkInterval) {
  setInterval(function() {
    var xhr = new XMLHttpRequest();
    xhr.open('GET', window.location.toString());
    xhr.onreadystatechange = function() {
      if (xhr.readyState == XMLHttpRequest.HEADERS_RECEIVED) {
        var changed = parseFloat(xhr.getResponseHeader("Changed"));
        if (changed > window.performance.timing.navigationStart) {
          location.reload(true);
        }
      }
    }
    xhr.send();
  }, checkInterval);
}