Using the navigation timing API to test the performance of a page

performance.js

(function () {

  var t = window.performance.timing;
  var timings = [];

  timings.push({
    label: "Time Until Page Loaded",
    time: t.loadEventEnd - t.navigationStart + "ms"
  });
  timings.push({
    label: "Time Until DOMContentLoaded",
    time: t.domContentLoadedEventEnd - t.navigationStart + "ms"
  });
  timings.push({
    label: "Total Response Time",
    time: t.responseEnd - t.requestStart + "ms"
  });
  timings.push({
    label: "Connection",
    time: t.connectEnd - t.connectStart + "ms"
  });
  timings.push({
    label: "Response",
    time: t.responseEnd - t.responseStart + "ms"
  });
  timings.push({
    label: "Domain Lookup",
    time: t.domainLookupEnd - t.domainLookupStart + "ms"
  });
  timings.push({
    label: "Load Event",
    time: t.loadEventEnd - t.loadEventStart + "ms"
  });
  timings.push({
    label: "Unload Event",
    time: t.unloadEventEnd - t.unloadEventStart + "ms"
  });
  timings.push({
    label: "DOMContentLoaded Event",
    time: t.domContentLoadedEventEnd - t.domContentLoadedEventStart + "ms"
  });

  var navigation = window.performance.navigation;
  var navigationTypes = { };
  navigationTypes[navigation.TYPE_NAVIGATENEXT || 0] = "Navigation started by clicking on a link, or entering the URL in the user agent's address bar, or form submission.",
  navigationTypes[navigation.TYPE_RELOAD] = "Navigation through the reload operation or the location.reload() method.",
  navigationTypes[navigation.TYPE_BACK_FORWARD] = "Navigation through a history traversal operation.",
  navigationTypes[navigation.TYPE_UNDEFINED] = "Navigation type is undefined.",

  console.group("window.performance");

  console.log(window.performance);

  console.group("Navigation Information");
  console.log(navigationTypes[navigation.type]);
  console.log("Number of redirects that have taken place: ", navigation.redirectCount)
  console.groupEnd("Navigation Information");

  console.group("Timing");
  console.log(window.performance.timing);
  console.table(timings);
  console.groupEnd("Timing");

  console.groupEnd("window.performance");

})();

Saved as a snippet in Chrome devtools