Sencha Architect 2.0 is a visual app building tool for building webapps built upon lessons learned from their earlier Ext Designer tool. It's not cheap but it looks interesting and has a lot of fans.

Spaceport.io is a powerful cross platform HTML5 based game development engine. Amongst others, BBC Worldwide has made a significant investment into the company. This comes just two months after Game Closure took $12m in investment. It's an interesting time for HTML5 gaming.

PhoneGap is an HTML5 app platform that allows you to author native applications with web technologies (like JavaScript!) Amongst other things, it now includes the 'Cordova-JS' unified JavaScript layer.

WebKit support for remote debugging (a way to debug Web pages in a browser 'over the wire') began almost a year ago, but now it has reached version 1.0 and WebKit is dedicated to supporting it and maintaining compatibility.

Tab Atkins Jr. has announced that 'CSS Variables' has been published as a first public working draft at the W3C. This module introduces a family of custom user-defined properties known collectively as variable properties which can be used throughout a CSS document (think Sass).

How can you get two or more browser tabs/windows to talk to each other? You could go all AJAX on us, but what about keeping it all client side? Carlos Aguayo presents a simple demo of using localStorage to pull it off.

Sean Soria talks about building a 'city builder' style game using HTML5 and ensure it runs quickly on Facebook on desktops, as well as on iOS and Android devices. What did they learn? Here are the highlights.

This tutorial covers debugging JavaScript using regular breakpoints set on JavaScript code and breakpoints targeted at UI and network aspects of an application.

RIM's forthcoming BlackBerry 10 platform boasts WebGL and HTML5 support. What, how, and why? Alex Kinsella and Adam Stanley from RIM's Developer Relations Team explain.

An interesting writeup of converting a game designed for Xbox Live Indie Games to JavaScript and HTML5 using the JSIL .NET to JavaScript compiler. You can also give the game a go if you like.

It wanders around a bit, but this extensive article by Pascal Rettig covers a lot of interesting points relating to HTML5 game development for mobile devices (with a focus on iOS devices) including sound, performance, and viewport considerations.

A handy online cheatsheet and reference showing off the various element selectors in CSS3. Click on a selector to see some demo code and browser support info.

Googler Boris Smus has put together some best practices in device detection and released Device.js. It lets you do semantic, media query-based device detection without needing special server-side configuration.

CreateJS is a suite of modular libraries and tools which work together to enable rich interactive content on open web technologies via HTML5. It includes EaselJS, TweenJS, SoundJS and PreloadJS as well as Zoe, an app for converting SWF animations to sprite sheets.

Bills itself as 'a full version of Twitter's Bootstrap with themes, enhancements, and other goodies.'

An awesome WebGL powered game where you get to fly an X-Wing along a trench of the Death Star. Simple yet effectively designed.

Did you know you can apply CSS transformation effects to list elements that occur when scrolling through that list? Hakim El Hattab shows off the effect in various forms.

A demo (for Google Chrome only) involving mixing multitrack audio with using the Web Audio API.

Senses bills itself as an 'HTML5 media center' and as a 'next generation multimedia project'. In essence, it's an attempt at bringing a media center style experience to the Web.

The cutting edge of Chrome now offers a specialized date picker for HTML5 form elements with a type of 'date'. Still a way from hitting the mainstream Chrome releases though.