Adobe is open-sourcing its ActionScript Virtual Machine. It has contributed the code to the Mozilla Foundation, provider of the free Firefox Web browser, marking the biggest single contribution to the foundation since it was established in July 2003.

Putting the contribution to use, open-source powerhouse Mozilla will host a new project, called Tamarin (details will be available here), to accelerate the development of the ECMAScript Edition 4 standard language. Contributions to the code will be managed by a governing body of developers from both Adobe and Mozilla, and Mozilla will use that in the guts of SpiderMonkey, the core JavaScript engine embedded in a future version of Firefox.

• What does it mean?

Another way to read this: Adobe is offering up secrets from its popular Flash player, hoping it will become the de facto standard on which tomorrow’s Web applications will be built. Adding weight to the offering, Mozilla plans to release a version of Firefox built from the foundation of this ActionScript VM code sometime in 2008.

Frank Hecker, executive director of the Mozilla Foundation, said that by taking advantage of Adobe’s code, “any application that is highly dependent on JavaScript performance” could see benefit. As examples, he mentioned Web-based productivity suites, rich e-mail clients, and photo-sharing sites. “Firefox itself is largely written in JavaScript.”

Unfortunately for those of us who aren’t programmers, the impact of this is tough to grasp. Does it mean Adobe will help other people build Flash authoring products? Adobe says no.

What I think it means is that Adobe is taking the covers off the engine that presents all that video from the likes of YouTube, hoping that companies large and small will choose it as the common engine for presenting Web 2.0 software like Google Docs & Spreadsheets, and Yahoo Maps. Here’s an Adobe employee’s take on the value of the ActionScript VM.

“Adobe’s work on the new

virtual machine is the largest contribution to the Mozilla Foundation

since its inception,” said Brendan Eich, chief technology officer of

Mozilla Corporation and creator of JavaScript, in a prepared statement. “Now Web developers

have a high-performance, open source virtual machine for building and

deploying interactive applications across both Adobe Flash Player and

the Firefox Web browser. We’re excited about joining the Adobe and

Mozilla communities to advance ECMAScript.”

• Inviting competition

Adobe’s move eventually could open up the possibility of other companies “doing their own Flash player,” or otherwise competing with Adobe, CEO Bruce Chizen said in an interview with me several days ago, before the Mozilla deal was complete. But it’s a risk Adobe’s willing to take. “Shame on us if we can’t out-innovate the competition.”

When talking about Adobe’s ongoing challenge to build its business while also being open with the developer community, Chizen offered some reflections that may illuminate his thinking behind the ActionScript VM move:

“It really is a tension between those who can be blinded by making money,

and those who want to do what’s right for the [developer]

community regardless of the business outcome. My job is to balance the

needs of both communities. Where these issues come to a head is in meetings

where the champion for a standards body is at odds with those who are

responsible for making sure that we deliver the appropriate results for

our shareholders,” Chizen said. “I have to decide.”

InformationWeek has this angle:

Adobe’s decision to open source the Flash scripting engine can also be

seen as an effort to counter Windows Presentation Foundation/Everywhere

(WPF/E), a subset of Microsoft’s graphics display platform that will compete with Adobe’s Flash technology.

The biggest threat to Flash, says Richard Monson-Haefel, senior analyst

at the Burton Group, is Ajax and Microsoft. “I think what they’ve

realized is Ajax has just taken off,” he says. “It’s either jump on the

Ajax ship or get left behind.”

• What do you think?

Clearly, I’m no expert on Web development or ActionScript. (Could you tell?) Often, readers know more. So weigh in below: What do you think? Is this a good move by Adobe? Will SpiderMonkey rule? And what does it mean for Microsoft?