zoneminder/web/skins/classic/views/js/zones.js

// Manage the Add New Zone button
function AddNewZone(el) {
  url = el.getAttribute('data-url');
  window.location.assign(url);
}

var monitors = new Array();

function initPage() {
  for ( var i = 0, length = monitorData.length; i < length; i++ ) {
    monitors[i] = new MonitorStream(monitorData[i]);

    // Start the fps and status updates. give a random delay so that we don't assault the server
    var delay = Math.round( (Math.random()+0.5)*statusRefreshTimeout );
    monitors[i].start(delay);
  }

  // Manage the BACK button
  document.getElementById("backBtn").addEventListener("click", function onBackClick(evt) {
    evt.preventDefault();
    window.history.back();
  });

  // Disable the back button if there is nothing to go back to
  $j('#backBtn').prop('disabled', !document.referrer.length);

  // Manage the REFRESH Button
  document.getElementById("refreshBtn").addEventListener("click", function onRefreshClick(evt) {
    evt.preventDefault();
    window.location.reload(true);
  });
}

window.addEventListener('DOMContentLoaded', initPage);