SimplePie is a code library intended to make it ridiculously easy for people to manage RSS and Atom Feeds.

Its an easy to use API that handles all of the dirty work when it comes to fetching, caching, parsing, normalizing data structures between RSS and Atom formats, handling character encoding translation, and sanitizing the resulting data.

Flexible enough to suit beginners and veterans alike, SimplePie is focused on speed, ease of use, compatibility and standards compliance.

SoundManager 2 is a free JavaScript Audio API supporting MP3, MPEG4 and HTML5 audio + RTMP (experimental), providing reliable cross-browser / platform audio control.

This free Javascript audio API makes it easier to play audio using Javascript, checkout few of its features below:

• 100% Flash-free MP3 + MP4/AAC where supported
• Works on iPad, iPhone iOS 4
• Fallback to Flash for MP3/MP4 support
• RTMP / Flash Media Server streaming support (new, experimental)
• Audio buffering state/event handling

Mashi JavaScript Timeline Toolkit is an open source Javascript toolkit that brings timeline-driven animation and interaction capabilities to your web site.

Animation Toolkit Features

• HTML5 Canvas supported
• No web server or browser plug-ins required
• Easily Extendable via Plugins
• Enables to get elements from external (valid) HTML or XML files

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.

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.

Open Video Player (OVP) is an initiative encompassing the use of open standards, best practices, and established development methodologies in the development of media player applications.

The Open Video Player added support for HTML5 with their new member named: OVP for HTML5 <video>. This project provides a simple JavaScript library to accelerate the development of HTML5 <video> experiences.

Features

• Intelligent player technology selection
• Standardized user interface across player technologies
• Native mRSS Playlist support
• Create and modify themes for the controls using standard CSS & Javascript
• Uses industry standard jQuery

Show Slow is an open source tool that helps monitor various website performance metrics over time. It captures the results of YSlow and Page Speed rankings and graphs them, to help you understand how various changes to your site affect its performance.

Show Slow can be used as a free online service and can be downloaded to install on your own server.

Alloy UI is an HTML5 CSS3 Application Framework & and a rich widgets toolkit to deliver rich web applications with enjoyable user experiences.

It comes with many ready to use components including:

• Image gallery
• Calendar
• Color picker
• Charts
• Tooltips

This HTML5 CSS3 Framework is built upon YUI3 – Yahoo!’s JavaScript / CSS library and comes with many functional demos.

Timeplot is an open source, DHTML-based AJAX data visualization widget for plotting time series and overlay time-based events over them.

You can draw multiple plots in the same timeplot, either using the same geometry of another one or not, depending on what you want to achieve.

With this open source data visulization widget, users can create timeplots which are very easy to customize.

• Stroke and fill Plot colors customization
• Multiple timeplots
• On-Demand plot values

InfoVis is a JavaScript Toolkit for creating Interactive Data Visualizations for the web built upon the concepts Modularity, Extensibility and Composability.

Supports multiple data representations like Treemaps, Radial Layouts, HyperTrees/Graphs, etc…

InfoVis components are:

• Powerful and easy to use
• Support live data updates and multi-valued data
• Mutable Visualization classes & can add/override any method
• Useful for combined visualizations

This JavaScript Interactive Data Visualizations Toolkit is open source and can be used with your favorite DOM manipulation framework.