Cached Commons is a collection of user-contributed javascript libraries that have been cached, optimized, and hosted on Github’s fast CDN.

The main goal is to aggregate the best-of Javascript and CSS libraries for rapid prototyping. It won’t have every javascript library because there’s 1000’s of jQuery Tooltip plugins out there, but only say 3 of them are really good.

You can easily download the libraries to your local project if you’d like, or feel free to directly link to the ones here.

Polymaps is a free JavaScript mapping library for making dynamic, interactive maps in modern web browsers. It creates image and vector tiled maps using SVG.

Polymaps provides speedy display of multi-zoom datasets over maps, and supports a variety of visual presentations for tiled vector data, in addition to the usual cartography from OpenStreetMap, CloudMade, Bing, and other providers of image-based web maps.

F->IT is an open source & easy to use web based FTP client that resembles Windows Explorer.

It supports:

• Drag and drop folders and files
• Edit highlighted source files
• Upload multiple files

Tweet! is an unobtrusive JavaScript plugin for jQuery to add twitter on your website. Its small and efficient script that will not slow down or pause your page while tweets are loading.

With Tweet!, you can:

• Customize look and feel with your own stylesheet
• Display tweets from multiple accounts!
• Display tweets from a twitter search, or from your own feed
• Display your avatar

ColorPicker is a free Javascript color picker that can display and let you choose the entire color palette (~16.78 mil. colors) in 6 different color modes.

This highly customizable and easy to install Javascript color picker comes in 4 different sizes with different feature levels.

Features

• Draggable Color pickers
• Skinn-able with CSS
• Accessible & Compact Design

Style your markup right in your browser with an in-browser element selector and CSS editor, Brosho. Generate the CSS code of altered elements with one click and use it in your own stylesheet.

Stop switching between editor and the browser for changes, tweaks and enhancements, changes will occur immediately without reloading the page. Once you are done designing your mockup you can generate the CSS code, paste it to your stylesheet.

TranslateThis Button is a lightweight free Javascript translation widget. It translates any page quickly using Ajax and the Google Language API.

This widget is cross browser compatible and translates your website into 52 languages; just copy and paste the TranslateThis Button anywhere on your site.

TranslateThis Button is available as a free javascript translation widget and it also comes as a free translation plugin for Wordpress.

You may have seen the flash content slider over at MLB, Louis Lazaris shared a very nice tutorial on recreating this content slider using jQuery and CSS3.

This CSS3 content slider supports:

• Auto-hide thumbnails
• Navigation controls to view specific slide along-with next / previous button controls

PlotKit is a Chart and Graph Plotting Library for Javascript, aimed at web applications that require plotting series of data in modern web browsers.

It has support for HTML Canvas and SVG via Adobe SVG Viewer and native browser support. PlotKit is easily extensible to include other rendering engines, styles and layouts.

baseJS is a lightweight Javascript mobile framework intended for use with Mobile Safari on the iPhone and iPod Touch; it also works with Firefox and all WebKit-based browsers.

By providing shortcuts and reusable methods, baseJS helps you write code to be lightweight and expendable, perfect for the mobile web.

Features

• Falls back on Sizzle selector library for iPhone 1.x (if query selector support unavailable)
• Encourages use of CSS Transitions and Animations
• Object-oriented mobile javascript framework
• Easy to extend

baseJS is not useable with Internet Explorer.