How to Correctly Defer Loading of JavaScript

Stumbled upon this article about defering the loading of JavaScript in a good way.

Using the old ways of placing scripts in the footer or other causes a big delay in the document ready event. Which is when your page has actually finished loading. This method triggers the loading of the script on that same event.

The methods of inlining, placing scripts at the bottom, using “defer” or using “async” all do not accomplish the goal of letting the page load first then loading JS and they certainly do not work universally and cross browser.

Now I need to figure out how to use this in conjuction with Ember the best way. Showing content to the user ASAP should be a top priority. This gets tricky when you have a large library to load.