JavaScript is back in fashion, with Ajax libraries and applications redefining the web-based user experience. The JavaScript programming language standard is also finally receiving significant investment, both to fix bugs and to address the demands of “programming in the large” that inevitably arise in building modern browser-based applications, all while preserving compatibility with the mountains of JS on today’s web.

The long-awaited next version of JavaScript, ECMAScript Edition 4 or “JavaScript 2”, is being specified this year by an ECMA group including representatives from Adobe, Apple, Microsoft, Mozilla, and Opera. The specification should be wrapped up in the first half of 2007, and I will present some of the new features of the language, demonstrated via a prototype implementation in Mozilla Firefox.

Even with aggressive commitments from Mozilla, Opera, and Adobe to finish and ship implementations of Edition 4, many users will not be able to run applications that take advantage of the new capabilities of JavaScript 2 for some time to come. In order to bring the power of JS2 to bear more quickly, and to aid migration, an open source JS2-to-JS compiler is in development, and will be presented here. We intend that this tool will make JS2 a viable choice for developers soon—this year, in fact.

JavaScript has been a crucial part of the web for over ten years, and it will be around at least that much longer, so the ECMA group is designing for the longer haul. The aim is to support not only “programming in the large”, but also metaprogramming, so that future evolution of the language can happen above the core ECMA specification, in the standard library ecology.

These design decisions, product commitments, and tool developments all contribute to one key goal: making web applications better and easier to build, for tomorrow and the next decade alike.