What is a reliable way to calculate actual (web) page loadtime

javascript performance pageload
David Laing picture David Laing · Mar 20, 2009 · Viewed 17.9k times · Source

I'm interested in knowing the actual average page loadtime for my webapplication.

Simplistically, how log does my average visitor wait before they can start using a page on my site. From when they click the link to my site until the site is finished rendering & ready to accept input.

The standard solution seems to be to use Javascript to compare the time from a script in the until a script in the window.onload() event.

(See: http://www.dreamincode.net/code/snippet1908.htm)

This doesn't seem like a very acturate measure to me, as it ignores the time taken to resolve my domain & receive enough HTML content to begin Javascript parsig.

It also looks like Safari fires window.onload before the page has actually finished loading (http://www.howtocreate.co.uk/safaribenchmarks.html).

Any ideas?

Is it possible to get the time a the current request was initiated via Javascript?
What event fires after everything is ready reliably across all browsers?

Answer

zadubz picture zadubz · Apr 27, 2012

http://www.webpagetest.org/ is an excellent resource for measuring load time

Also google chorme dev tools has a Timeline panel where you can record events, Here is a 2.5minute video showing you how Timeline in google chrome works http://www.youtube.com/watch?v=RhaWYQ44WEc

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