PxLoader is a simple JavaScript library for creating preloaders and resource downloaders for HTML5 apps
PreloadJS makes it easy to preload your assets: images, sounds, JavaScript, fonts, JSON, and text data
fakeLoader.js is a lightweight jQuery plugin that helps you to create an animated spinner with a fullscreen loading mask to simulate the page preloading effect.
A tiny 1kb JavaScript library for preloading assets on the browser via XHR2. It provides the ability to load assets of different file types and composite progress events.