Palm - Project Ares
http://ares.palm.com/Ares/about.html

According to Palm "Project Ares is the first mobile development environment hosted entirely in a browser, lowering the barriers for web developers to jump into mobile development."

Project Ares is the first mobile development environment for Palm's WebOS, hosted entirely in a browser

browser based IDE for WebOS

Like webOS, Project Ares embodies Palm's belief that the future of mobile will be built on the web. Project Ares aims to enable a next-generation mobile development workflow, in which developers move quickly and seamlessly from editing in a browser, to debugging on a device, to selling applications in Palm's App Catalog or on the web.