[webkit-dev] optimizing browser handling of Facebook Timeline scrolling

Geoffrey Garen ggaren at apple.com
Mon Feb 13 21:33:44 PST 2012

>> (1) 50% of time spent in style calculation forced by accessing element.offsetHeight in JavaScript.
> Geoff - I am going to bite the bullet and rip this logic out. We are
> pushing too much complexity into the browser.

Bear in mind that I didn't do enough analysis to explain why the .offsetHeight code was so costly. It may be possible to tune this code and keep it in the browser. For example, you could maintain a separate document for measuring items, so you could measure without reflowing the main document.

>> (2) 50% of time spent painting images... This is a simple speed vs quality tradeoff. If you down-sampled the images on the server, they'd download and paint much faster.
> Geoff - Painting images specifically, or just repainting the page in general?

Painting images specifically.


More information about the webkit-dev mailing list