WebPerfDays NY

gistfile1.txt

Prefetch/Prerender @igrigorik
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Check out "connection view" in webpagetest

Can be fired through js too.

Uses Page Visibility API to not mess up analytics.


3rd party perf
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3rd party is not:
JQuery
CDN
etc.


GPU/CSS
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Turn on continuous page repainting to test

Colt McAnlis
...it's stuff you can't control:
Analytics
- Beacons
Widgets
- Like/Tweet/RSS stream widget
Ads
AB testing/Shopping cart personailation (MotionPoint/SiteSpect)

If a 3rd party is down, it can slow/freeze your page load.

You can defer execution on JS (download, but run later)

You can add an onload to a script tag.
You can add "async" as a param to a script tag.

Goal: Defer download

lazyload/pospone param for images (draft spec)

async=false <- execute async loaded scripts in order (Write this in JS)

Try a SPOF (no third party) test <- With webpagetest 


Responsive images
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srcset
http://mobile.smashingmagazine.com/2013/08/21/webkit-implements-srcset-and-why-its-a-good-thing/