The following graph illustrates the timing attributes defined by the PerformanceTiming interface and the PerformanceNavigation interface with or without redirect, respectively. Attributes underlined may not be available in navigation involving documents from different origins. User agents may perform internal processing in between timings, which allow for non-normative intervals between timings.
- navigationStart: Time after the previous document begins unload.
Or, in other words, tells us when the user initiated the page load, either by clicking a link, or entering it into their browser’s URL bar.
Now you have more tools, at least at client-side, to measure the performance of your pages.
- W3: The window.performance attribute
- Microsoft MSDN: Navigation timing
- Mozilla MDN: Navigation timing
Note: don’t forget to clean all console calls in your production code, also, check the browser compatibility (Mozilla MDN) since is not supported in all browsers.
Hope you find this information useful!