Navigation Timing API

The Navigation Timing API introduces a JavaScript interface for gaining access into key insights into the performance times of each of the stages of page load. With over 21 attributes that break down page load, you can draw some interesting and informative conclusions about where your page or server times may be bottlenecking. As the page loads these various timings are captured and stored in epoch time on the window.performance.timing object. You can see below at what point these timings occur during load.

Timing attributes

Useful benchmarking calculations with some of the 21 attributes:

  • Document parsing: domInteractive – domLoading
  • Network Latency: responseEnd – fetchStart
  • Page load time: loadEventEnd – responseEnd
  • Navigation and page load time: loadEventEnd – navigationStart

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