Pluginweb.Net

John Resig has analyzed JavaScript library loading speed by looking into the recent PbWiki testing results.

He delves into the fact that file size != speed and puts out the simple formula:

Total_Speed = Time_to_Download + Time_to_Evaluate

We also seem to obsess about packing and minification, where it often does give us that much since the act of gziping the data often does enough. Thay being said, if you have a lot of JavaScript it can certainly be worthwhile. It matters the most that the frameworks themselves (which are normally bigger than the app) play nice.

In fact, walk around your site with Firebug/YSlow and see if you have set your headers up correctly. After watching Steve Souders at work, it boggles my mind how many big sites are misconfigured (let alone small ones).