Dependency

jQuery plugin for async and sync JavaScript load.

whenSlow

Execute a function (e.g. show loading status) when a Promise is slow.

Dynamic Widget

Dynamic Widget is a plugin for JQuery UI that automates lazy loading JS and CSS for your JQuery UI widgets without the need to worry about includes.

jQuery Ajax Loading

jQuery Ajax Loading.

VoilĂ 

A jQuery plugin that provides callbacks for images, letting you know when they’ve loaded.

Is Loading – Show feedback to your visitors

Easy jQuery plugin to show visual feedback when loading data or any action that would take time. Also can disable form elements and put an overlay an specified area or whole page.