IE 9 'platform preview' released at MIX10

Microsoft announced the availability of an Internet Explorer 9 "platform preview" at Tuesday's MIX10 keynote address.

Microsoft Windows Division President Steven Sinofsky and IE General Manager Dean Hachamovitch announced at the Las Vegas event that developers and the general public can get their hands on the IE 9 platform preview as of Tuesday.

The preview of Microsoft's newest Web browser is accessible at Microsoft's test drive site here.

The IE 9 platform preview isn't a fully functional browser or even an alpha version. It lacks an address bar and many other common browser user interfaces. Microsoft is releasing it to get feedback from developers, and the company plans to release updates of the platform every eight weeks. Users can run the various tests prebuilt into the platform preview and compare those results with the test performance of other browsers.

The big news for developers is Microsoft's strong commitment to the Worldwide Web Consortium's (W3C's) HTML5 recommendation in producing IE 9. The company previously announced in January that it had rejoined the W3C's Scalable Vector Graphics (SVG) Working Group, and IE 9 will tap into SVG natively instead of relying on a plug-in.

"We love HTML5 so much, we want it to actually work, and in IE 9 it will," Hachamovitch said during the keynote. "And so in IE 9, we will do for the rest of the Web platform what we did with CSS 2.1 in IE 8." He was referring to the various tests Microsoft wrote for the W3C's CSS 2.1 spec.

Hachamovitch emphasized how "painful" it has been for developers to write markup code that does not run the same way across different browsers. The goal is to write code once and have it display in the same way across different browsers. Microsoft's IE 6, still in widespread use today, has long been disliked by many developers who have complained about its lack of standards support.

(To address the forthcoming and changing HTML5 spec, the Microsoft team recommends that developers test for features, rather than the browser type, in their code.)

Some compatibility problems will still be apparent when users run the IE 9 platform preview tests and compare those results with test results in other browsers. Microsoft's practical response to this issue has been to collect usage data and write tests for the HTML5 spec. Microsoft just submitted more than "100 additional tests of HTML5, CSS3, DOM and SVG to the W3C" on Tuesday, according to the IE blog.

Microsoft has its hands at the helm of the W3C's standards efforts. Paul Cotton, Microsoft group manager for Web services standards and partners, currently serves as co-chair of the W3C HTML Working Group. Kris Krueger, Microsoft principal test lead for IE, serves at the chair of the HTML5 Working Group.

Cotton outlined Microsoft's standards efforts in a recent W3C blog post. He noted that people refer to HTML5 in various ways, including the W3C spec and the ECMAScript-262 Language. HTML5 is still at the working draft stage, and no one seems to know when it will reach the final W3C candidate recommendation stage. Meanwhile, browser makers are attempting to implement the HTML5 spec using different technologies and rendering engines. And that accounts for the various incompatibilities seen in tests.

Hachamovitch said during the keynote that if HTML5 is done right, it will make Web applications seem "more like real apps." Microsoft designed IE 9 to take advantage of SVG by tapping into the power of the underlying hardware, specifically graphics processing units (GPUs). Using GPUs for SVG unburdens the client machine's CPU to handle other tasks. Microsoft also sped things up by leveraging a new script engine for IE 9, code-named "Chakra," which was announced Tuesday. According to the IE blog, "Chakra compiles JavaScript in the background on a separate core of the CPU, parallel to IE."

Microsoft is claiming that IE 9 "is the first browser to provide hardware-accelerated SVG support," according to the IE blog. During the keynote, dual videos were run using HTML5 video, which Microsoft defines as "HD-encoded, H.264 720p" in the IE blog. Microsoft claims that video performance in IE 9 is enhanced using Windows, which has the ability to "take advantage of PC hardware for video decoding."

Microsoft's IE 9 platform preview lags on certain benchmarks, such as the Acid3 score, where it passed 55 tests out of 100, although Microsoft tends to be a critic of that test. According to Jason Weber, principal program manager lead for IE, Acid1 was originally a W3C test, but subsequent versions of the test have not been W3C efforts. Hachamovitch said during the keynote that IE 9's Acid3 scores will improve, but he implied that the tests in Acid3 were of little-used features.

The IE 9 platform preview did much better in a comparison of JavaScript performance via the WebKit SunSpider test. IE 9 platform preview edged out Firefox version 3.7, alpha 2 in terms of speed in a SunSpider test published on the IE blog.

In general, Microsoft is basing its IE 9 development efforts on a tool that measures the top APIs used across 7,000 Web sites. So, support for some HTML5 features will not make it into the first release of the new browser.