LABjs
Loading And Blocking JavaScript: On-demand parallel loader for JavaScript with execution order dependencies
RequireJS
A file and module loader for JavaScript
Script.js
Asyncronous JavaScript loader and dependency manager
Layzr.js
A small, fast, modern, and dependency-free library for lazy loading.
jQuery Pjax
pushState + ajax = pjax
Nanobar
Very lightweight progress bars. No jQuery
Aload
Loads images, scripts, styles, iframes, videos and audio asynchronously.
Pilpil
Pilpil - Progressive Image Loading
Head js
The only script in your HEAD. Head JS loads JavaScript files in parallel like images without blocking the page. Your page will be faster. Even with a single combined file.
Query Loader2
Version of the QueryLoader by Gaya Design. Preload images with ease.
Queue
Yet another asynchronous helper library for JavaScript. 387 bytes minified and gzipped!
Sea.js
A Module Loader for the Web
Imagesloaded
JavaScript is all like "You images done yet or what?"
Almond
A minimal AMD API implementation for use after optimized builds
Blazy
bLazy is a lightweight lazy loading and multi-serving image script. It's written in JavaScript why it doesn't have any dependencies for 3rd party libraries like jQuery. bLazy is working in all modern browser including IE7+.
Lazyload
Tiny, dependency-free async JavaScript and CSS loader.
Lazysizes
High performance and SEO friendly lazy loader for images (responsive and normal), iframes and more, that detects any visibility changes triggered through user interaction, CSS or JavaScript without configuration.