TIL: The AirBnB tech-talks site (all the videos are on YouTube too) is pretty awesome! I don’t know how I managed to miss it for so long—they host a regular tech-talk by someone interesting every fortnight, and then make the video available for everyone—cool stuff!

This morning I watched the latest talk “Dive Into Performance” by Steve Souders (he also made the slides available!).

It runs a little over an hour, and is packed with awesome knowledge that you should probably try and jam into your skull. Some of it is pretty common-sense type stuff but there are some real gems in there.

A few of the things I picked up;
  • The nav timing spec (window.performance) is full of awesome information (all good browsers but only Chrome flavours of Webkit—WTF Apple?). MDN has some more interesting reading too.
  • webpagetest.org is even more amazing than I thought. You always learn a lot watching power-users, Steve is a Webpagetest.org power-user. This is a must for squeezing free speed out of your app/site.
  • Browser asset load order is != to document order. Modern browsers use speculative look-ahead parsing of a the document while blocked (say while waiting on a <script> tag) to actually eagerly-load content “further down” the document. Crazy stuff! According to a quote from Steve during his talk, the Chrome team attribute a ~30% page speed increase to this.