Example of gathering request timing information using the Navigation timing API

Network-Timing-API.js

  function getPerformanceData() {
    var perf = window.performance || window.msPerformance || window.webkitPerformance || window.mozPerformance;
  
    if (perf) {
      var t = perf.timing;
      return [
        // Time required for domain lookup.
        t.domainLookupEnd - t.domainLookupStart,
        // Time to establish a connection to server.
        t.connectEnd - t.connectStart,
        // From connection established to first byte of data.
        t.responseStart - t.connectEnd,
        // First byte to last byte, or closed, including if from cache.
        t.responseEnd - t.responseStart,
        // From last byte of doc to start of domContentLoaded
        t.domContentLoadedEventStart - t.responseEnd,
        // domcontentLoaded to start of load event.
        t.loadEventStart - t.domContentLoadedEventStart,
        // click, back/forward, etc...
        perf.navigation.type,
        // No. of redirects on current domain.
        perf.navigation.redirectCount
      ].join(',');
    }
  }