preload 
Load images, scripts and CSS with XHR progress events where supported.
This has been written more for large, script/asset-heavy pages such as games or WebGL demos where the page is already going to take 5+ seconds to load. As such, it's not as small as it could be - I'd recommend LazyLoad if you're looking for a lightweight solution.
Usage
Work in progress.
License
MIT. See LICENSE.md for details.