Dion Almaer and Ben Galbraith, the leaders of the Developer Tools Lab, said the aim of the project is to follow the example of tools such as Google Apps in shifting desktop-based tasks to the Internet.

Almaer said in a blog post: "As a challenge, we wanted to take on an interesting project that you would normally think of as a desktop application, and see if it would fly on the web. Being developers, why not develop something that we know and use every day? Our code editor."

Shifting the code editor to the web should make it easier for developers to collaborate, and one goal of the project is to enable live-coding sessions, Almaer said.

The tool is browser-based, so developers should be able to access it from any device using a standards-compliant browser, he said. Other high-level goals include ease of use, integration of the command line, standards compliance and extensibility, he said.

The initial release is only a preview, intended to get users and other developers involved, and Mozilla's initial focus was on performance, Almaer said.

Mozilla said: "The initial prototype framework... includes support for basic editing features, such as syntax highlighting, large file sizes, undo/redo, previewing files in the browser [and] importing/exporting projects."

Bespin 0.1 supports commands similar to those used in Ubiquity, a Mozilla Firefox browser extension that allows users to execute a variety of tasks simply by typing a command into the browser. The developers plan eventually to unite Bespin and Ubiquity, Almaer said.

He wrote: "Bespin commands look like Ubiquity commands, and we want to fully integrate them."

The project is accessible from Mozilla Labs's website, and requires a browser that implements an HTML 5 feature called Canvas. The developers said they have tested Bespin on Firefox 3 and WebKit Nightly, a test version of the open-source framework underlying Apple's Safari browser.