W2UI: New JavaScript UI Library

Complete set of JavaScript UI widget for development of data-driven web applications. Includes layout, grid, toolbar, sidebar, tabs, forms, fields, popup, overlay

BlockUI

Simulate synchronous ajax by blocking – not locking – the UI. This plugin lets you block user interaction with the page or with a specific element on the page. Also great at displaying modal dialogs.

SimpleModal

SimpleModal is a lightweight jQuery plugin that provides a simple interface to create a modal dialog

OmniWindow

Extremely customizable modal window plugin for jQuery with 150 lines of code, written specially for programmers.

jQuery mb.containerPlus

This is a useful plug in to build full featured and fully skinnable containers. The container can be set to draggable, resizable, collapsable and minimizable.

SlipHover

Apply direction aware 2D/3D hover effect to images

Loading Overlay

jQuery Loading Overlay Plugin

plainOverlay

The simple jQuery Plugin for customizable overlay which covers a page, elements or iframe-windows that is specified.

Magneticmediajs

Magneticmediajs is a library that allows media content (images, videos, maps, HTML & more) to be displayed efficiently and with style

jQuery Selz

Open Selz.com product hyperlinks in overlay to let your customers complete their purchase directly onto your site.