The following script shows how a developer can use the PerformanceNavigationTiming interface to obtain accurate timing data related to the navigation of the document:

PerformanceNavigationTiming.js

function init() {
  var navigationTiming = performance.getEntriesByType("navigation")[0];
  if (window.console) {
    console.log("Name: "       + navigationTiming.name      + "\n" +
                "Entry Type: " + navigationTiming.entryType + "\n" +
                "Start Time: " + navigationTiming.startTime + "\n" +
                "Duration: "   + navigationTiming.duration  + "\n" +
                "Unload: "     + (navigationTiming.unloadEventEnd -
                                  navigationTiming.unloadEventStart)  + "\n" +
                "Redirect: "   + (navigationTiming.redirectEnd -
                                  navigationTiming.redirectStart)     + "\n" +
                "App Cache: "  + (navigationTiming.domainLookupStart -
                                  navigationTiming.fetchStart)        + "\n" +
                "DNS: "        + (navigationTiming.domainLookupEnd -
                                  navigationTiming.domainLookupStart) + "\n" +
                "TCP: "        + (navigationTiming.connectEnd -
                                  navigationTiming.connectStart)      + "\n" +
                "Request: "    + (navigationTiming.responseStart -
                                  navigationTiming.requestStart)      + "\n" +
                "Response: "   + (navigationTiming.responseEnd -
                                  navigationTiming.responseStart)     + "\n" +
                "Processing: " + (navigationTiming.loadEventStart -
                                  navigationTiming.responseEnd)       + "\n" +
                "Onload: "     + (navigationTiming.loadEventEnd -
                                  navigationTiming.loadEventStart)    + "\n");
  }
}