Swiffy converts Flash SWF files to HTML5, allowing you to reuse Flash content on devices without a Flash player (such as iPhones and iPads). Swiffy can't yet convert DoubleClick Studio creatives.

A set of small, responsive CSS modules that you can use in every web project.

Random & Responsive HTML 5, CSS3 Gallery with LazyLoad

spiffy
HTML5 site
templates

Gallerie / Slider sans javascript. CSS 3 pur.

Turbulenz is a modular 3D and 2D game framework for making HTML5 powered games for browsers and mobile devices.

A framework for developers who want to design, build and share cross device applications.

Easy, object orientated client side graphs for designers and developers

Bolt is a tool for Content Management, which strives to be as simple and straightforward as possible. It is quick to set up, easy to configure, uses elegant templates, and above all: It’s a joy to use. Bolt is created using modern open source libraries, and is best suited to build sites in HTML5 with modern markup.

Collie is a Javascript library that helps to create highly optimized animations and games using HTML 5. Collie runs on both PC and mobile using HTML 5 canvas and DOM.

Nanoko is a JavaScript modular framework enabling flexible and sustainable HTML5 applications development and their deployment on both mobile and desktop applications.

SpreadJS is a new product derived from the Spread Product Family, which is a set of spreadsheet components for application development on a variety of platforms. SpreadJS is sure to bring value to your web applications with time-saving features.

Audio5js is a Javascript library that provides a seamless compatibility layer to the HTML5 Audio playback API, with multiple codec support and a Flash-based MP3 playback fallback for older or unsupported browsers. The motivation for creating Audio5js is to provide a light-weight, library-agnostic, Javascript-only interface for audio playback in the browser.

Tumult Hype’s keyframe-based animation system brings your content to life. Click “Record” and Tumult Hype watches your every move, automatically creating keyframes as needed. Or, if you’d prefer to be more hands-on, manually add, remove, and re-arrange keyframes to fine-tune your content.

Allows you to upload files using HTML5 Gears, Silverlight, Flash, BrowserPlus or normal forms, providing some unique features such as upload progress, image resizing and chunked uploads.

Quintus is an easy-to-learn, fun-to-use HTML5 game engine for mobile, desktop and beyond!

Holmes is stand-alone diagnostic CSS stylesheet that can highlight potentially invalid or erroneous HTML(5) markup by adding one class — Read more

Moqups is a nifty HTML5 App used to create wireframes, mockups or UI concepts, prototypes
depending on how you like to call them.

wysihtml5 is an open source rich text editor based on HTML5 technology and the progressive-enhancement approach. It uses a sophisticated security concept and aims to generate fully valid HTML5 markup by preventing unmaintainable tag soups and inline styles.

jQuery Mobile: Touch-Optimized Web Framework for Smartphones & Tablets A unified, HTML5-based user interface system for all popular mobile device platforms, built on the rock-solid jQuery and jQuery UI foundation. Its lightweight code is built with progressive enhancement, and has a flexible, easily themeable design.