Microsoft Releases IE9 Platform Preview 7

Microsoft launches the seventh platform preview of its Internet Explorer 9 browser, which boasts a 345 percent improvement in JavaScript performance.

Exactly one year since it was first introduced at the Microsoft Professional Developers Conference 2009 (PDC), the software giant has announced the seventh Internet Explorer 9 Platform Preview.

With the new IE9 Platform Preview, Microsoft has increased the JavaScript performance of the browser by 345 percent since its introduction a year ago. IE9's performance on the SunSpider JavaScript benchmark is now 234.6 milliseconds. Microsoft launched IE9 Platform Preview 7 on November 17.

Microsoft also said there have been more than 13 million downloads of the IE9 beta since its launch. At PDC 2010, Microsoft said there had been 10 million IE9 downloads. The 2010 PDC ran October 28-29, just three weeks prior to the release of the seventh platform preview of IE9.

With the new platform preview, Microsoft has introduced new demos on IE Test Drive. Key demos for users to play focus on are: HTML5 Galactic, Shakespeare's Tag Cloud and the HTML5 Sudoku Solver game.

The seventh Internet Explorer 9 Platform Preview is available for download at:

Meanwhile, a Nov. 17 news report suggests that Microsoft may have gamed the SunSpider Benchmark to get such impressive results from the IE9 JavaScript engine, codenamed "Chakra."

In a Nov. 17 blog post, Dean Hachamovitch, Microsoft's corporate vice president for Internet Explorer, said, "Over the last few weeks, we've been tuning the JavaScript engine for more of the patterns we've found in real world sites." And he cautioned: "We've been consistent in our point of view that these tests are at best not very useful, and at worst misleading."

Hachamovitch also said:

""Real world websites use JavaScript to respond to user input, manipulate strings, and move objects around the screen, and much more. We looked at common patterns and made adjustments to IE9's script engine. You can try these examples (and more) at"Running these sites in other browsers like the latest Google Chrome or FireFox 4, shows significant performance differences...""

Before this seventh IE9 Platform Preview, Microsoft delivered a new platform preview every eight weeks. The seventh platform preview broke a record for how quickly Microsoft could deliver a new preview of the IE9 technology.

Regarding the pace of IE9 preview releases, Hachamovitch said:

""The cadence of IE Platform Previews reflects our point of view: the point of a browser is to run actual websites, not just benchmarks or samples that are hardwired for one browser. Our point of view starts with providing consistent quality to respect customers' time and includes delivering meaningful progress with each Platform Preview.""