TheOdinProject/theodinproject — pull request #46 by zkay (2014-04-05 01:54:01+00:00)
Title: Add :defer to JS in asset pipeline, speeds up page loads

See following for more info:

http://caniuse.com/script-defer

>The boolean defer attribute on script elements allows the external JavaScript file to run when the DOM is loaded, without delaying page load first.

Older, but explanatory:

http://www.schillmania.com/content/entries/2009/defer-script-loading/