The popular web player JW Player now has a HTML5 version after its well-known Flash and Silverlight ones.

JW Player For HTML5 is a totally skinnable and configurable player based on the <video> tag of HTML5.

It is built with jQuery, and for any browser without HTML5 support, falls back to the JW Player for Flash automatically.

The player can be set to display a poster image before and/or after the video.

Also, it is possible to make it auto-play, auto-repeat, start with a pre-defined volume and much more.

Considering the player falls back to Flash, the formats supported are also the ones that can be played by Flash:

• H264 baseline video / AAC low-complexity audio in the MP4 or MOV container
• Theora video / Vorbis audio in the OGG container
• VP6 video / MP3 audio in the FLV container
• Spark (H263) video / MP3 audio in the FLV container

P.S. The player is currently in beta status, does not have all the features of JW players but works pretty stable.

CwVideo is a toolkit for using and controlling HTML5 video with MooTools.

By simply providing an id to the video tag and calling a function, every property of the video can be reached in a MooTools way.

It supports the methods play, pause, top, rewind, move, volume, getNetworkState and more.

Also, there are 2 custom extensions built with the Fx.Slider:

• timeline
• volume slider

that offers a good looking and user-friendly experience.

ProtoFluid is a free web-based tool which eases web application testing on various screen sizes and orientations.

It simply asks you you to mention the website to be tested and the desired screen size (sizes for popular devices are predefined).

Once launched, you can see the website inside a modal box with the mentioned size, and with a click, you can change the orientation.

For anyone, who prefers to complete this task on the browser-side, web developer add-on has the resize function, but keep in mind that you can still use Firebug or other tools at the fullscreen view with such a web-based app.

Also, it lets you design for CSS3 compliant (mobile) browsers using Media Queries.

Html5Demos.com, created by Remy Sharp, is a website that is sharing a list of beautiful HTML5 demos and examples.

The list includes items using HTML5 features like video, audio, canvas, geolocation, drag'n drop, web storage and more.

Browsers that are compatible with every demo is mentioned as well and it is possible to filter them according to the browsers and/or HTML5 feature used.

Gradually is a simple MooTools image slider that can present the images in an order and display an informative text for each (which is sometimes all we need).

It makes use of the HTML5 canvas element to create a beautiful transition effect.

The slider simply requires an unordered list of images (hopefully, with the same size) and uses the alt tag value as the informative text.

Besides the width/height values, the duration and interval when image is switched can be set too.

P.S. The download link at the website currently has a typo (here is the working one).

Kaltura, an advanced video publishing platform, is sharing a free and open source HTML5 Video & Media JavaScript Library.

The library enables you to use the HTML5 <video>  and <audio> tags today with a cross-browser and consistent player.

It is a feature-rich library that is built on jQuery and jQueryUI which makes theming, customizing and extending easier.

The player supports the open media formats ogg theora/vorbis (if you're using h.264 formats, the library supports a smooth transition with fallback to h.264 sources).

Besides the video player, there is also a compact audio player with similar features.

It can gracefully identify the best playback engine (native HTML5, Flash, VLC or Java Cortado) for your settings and video format.

The player's interface is multilingual (with the help of language files), it is already integrated with MediaWiki and can be integrated into any other platform easily.

OSM Player is a highly customizable and open source HTML5 media player that is built with jQuery.

It is designed to dynamically play almost any media, whether it be HTML5 video – Flash video – Audio, etc.

For any non-standard media and browsers without HTML5 support, it can fallback to Flash.

OSM Player supports playlists and offers a seamless Youtube/Vimeo integration.

The playlist can optionally be hidden and the video can be displayed in fullscreen.

Also, the player generates direct and embed links to the media which is nice for anyone willing to include the content to their web pages.

As we know, Internet Explorer 6,7 and 8 do not support the new HTML5 elements which result in messy outputs.

However, thanks to Remy Sharp, there is the popular HTML5 enabling script which adds HTML5 capabilities to IE.

It is a great script and supports most of the HTML5 elements but missing one feature which is "printing HTML5 elements from IE"..

There is now an alternative named IE Print Protector which helps IE to render HTML5 elements correctly, both on screen and in print.

It simply replaces HTML5 elements with supported fallback elements (like div and span) when you print.

And, it doesn't forget to create temporary styles in parallel to the replaced ones to match the look and feel.

jStorage is a simple wrapper plugin for Prototype, MooTools and jQuery to store data on browser side.

It is lightweight (2kb) and uses HTML5 local storage if available or userData behavior in older versions of IE (Webkit SQLite is not supported).

The plugin works the same in Prototype, MooTools, jQuery and it is very easy to use as there are only 4 functions:

• set (save a key)
• get (retrieve the value of a key)
• deleteKey (remove a key)
• flush (clear the cache)

jStorage was known as DOMCached and renamed after various features being dropped.

Wadda is a lightweight JavaScript library that uses HTML5 canvas for zooming images.

It comes in 2 JS files, one for the common functions an the other for the wadda function.

The library simply displays the original-sized-image inside a "lens effect" that must be mentioned in the thumbnail's title tag.

Wadda has several options for customization like the zoom level, lens size, enable/disable lens fade effect and the x/y offsets from the mouse cursor.

It is compatible with every canvas-enabled browser and will work on others using the explorercanvas library.