Dart is done.

Well, not completely done -- anything not actually cancelled at Google is a constant work in progress -- but the company on Thursday announced version 1.0 of its controversial Web programming language. Dart is designed to improve on JavaScript when it comes to programmer efficiency and software performance for Web sites and Web apps.

The 1.0 release means Dart is now ready for real-world Web sites, not just for testing, said Dart project leader Lars Bak in a blog post. And even though lots of roadblocks mean it's not possible to use Dart directly on the Web, Google offers indirect mechanisms that could make it useful while Google tries to convince other browser makers Dart is worthwhile.

Google debuted Dart two years ago, and it announced version 1.0 at the Devoxx conference in Belgium. It consists of a new programming language that Google hopes will be easy for JavaScript coders to learn but faster for them to use, a software developer kit (SDK) to help people write programs, the Dartium version of the Chrome browser that can directly run Dart programs, and the dart2js utility that can convert Dart programs into JavaScript for browsers that lack support.

Like another browser app overhaul from Google called Native Client, Dart hasn't won fans among other browser makers. JavaScript is well understood, accompanied by countless helpful pre-written libraries of software, steadily improving in performance, and expected to improve with the forthcoming EcmaScript 6 version.

More Dart difficulties include educating programmers, building libraries, hiring browser programmers to improve its performance and fix its security problems. JavaScript may have its shortcomings, but adding a second, entirely new software foundation to the Web increases complexity dramatically. With countless Web pages using JavaScript, there's no way support for it could be removed even if Dart did catch on, and Google also is pushing hard to advance JavaScript.

But also as with Native Client, Google is showing a lot of patience with Dart. It's made significant changes to the SDK in the last two years, it argues Dart can significantly boost performance, and it's betting that programmers will like it it even if they just convert their Dart software into JavaScript when it's time to actually put it on the Web.

Eventually, that programmer interest will be the strongest argument that other browser makers should support Dart.

Google argues Dart is better that JavaScript when it comes to large-scale projects, something that's increasingly common with Web programming. One of the best examples is Google Docs, Sheets, and Slides, which are made of very complex JavaScript software. Making those projects easier to maintain and faster to run is the kind of thing a Web company like Google is powerfully interested in.

On Thursday, it directed attention to Dart performance. With the three benchmarks Google uses, Dart is 42 percent to 130 percent faster than JavaScript, and Dart2JS versions outpace the JavaScript equivalents for two of the three tests.

Google uses Dart internally for its own customer relationship management system and for its Google Elections site, the company said, but it's also got external allies, including Blossom for collaboration and organization among employees; the Soundtrap music recording site, the Mandrill e-mail delivery company, and the Montage photo book company.

Google also pointed to progress in supporting libraries of Dart code. In addition to those it ships with the Dart SDK itself, there are Dart versions of two higher-level libraries, AngularDart and Polymer.dart, that came from JavaScript.

That's a start, to be sure. But even though Dart 1.0 is finished, the Dart project overall still has a long way to go.