Microsoft Delivers Final Peek at IE9 Preview Before September Beta

Microsoft has made key improvements to its next-generation browser in the fourth and final platform preview of the Internet Explorer 9 technology prior to its beta release. Improvements include integrating the "Chakra" JavaScript engine into the IE9 browser.

Leading up to a beta version of Internet Explorer (IE) 9 in September, Microsoft has released another Platform Preview of the browser that features native JavaScript integration, hardware-accelerated HTML5 and much improved Acid3 scores, among other enhancements.

At the Microsoft Financial Analyst Meeting on July 29, Microsoft's chief operating officer, Kevin Turner, said Microsoft will deliver a beta of IE9 in September.

"We're really excited about IE9, which will be beta and coming out in September," Turner said.

Since announcing its plans to deliver a next-generation browser known as IE9 at its MIX 2010 conference in March, Microsoft has released preview versions of IE9 for developers to test about every eight weeks or fewer. A new Platform Preview release now enables the company to make that eight-week time frame for getting a beta out in September.

Going by the progress Microsoft has made in its previous Platform Previews, you might expect to see enhancements to the company's "same markup" strategy, improved browser performance, greater compatibility and compliance with standards, enhanced HTML5 support, more test cases, and improved Acid3 test scores. With IE9 Platform Preview 4 you get all that and more.

Yet perhaps the standout feature of the several new and improved ones is the integration of the IE9 JavaScript engine into the browser itself rather than being simply bolted on.

In an Aug. 4 blog post on the new preview, Dean Hachamovitch, Microsoft's general manager of Internet Explorer, said:

"The fourth Platform Preview moves the new JavaScript engine, codenamed Chakra, inside IE9 and brings them together into one single, integrated system.

"Through this deep integration, the performance of real world websites significantly improves, and IE9 becomes the first browser to have a shared DOM between the browser and the script engine based on ECMAScript5. The benefits start with real-world performance and consistency."

Hachamovitch said before the Chakra engine was integrated inside the browser, developers using script engines for various languages had to communicate through the Microsoft Component Object model (COM), which could cause performance problems. And each script engine had its own language-specific view of the Document Object model (DOM), which created discrepancies, he said.

However, "In the fourth Platform Preview, we've moved the JavaScript engine inside IE9," Hachamovitch said in his post. "With this change, communication between the browser and script engine is now direct, which significantly improves performance for real world websites. We now have a single DOM, shared across all browser subsystems including JavaScript. This change ensures a consistent and interoperable view of the document. And this single DOM is now based on ES5 (ECMAScript 5), which prepares the entire system for the future."

In addition, Hachamovitch said, "The fourth Platform Preview of Internet Explorer 9, available now, shows the opportunity of fully hardware-accelerated HTML5. You can run new test drive samples that show modern SVG and native JavaScript integration in action. In March, we promised to deliver platform preview releases approximately every eight weeks. With this installment, you will find more performance and more support for the same markup. You'll also find many fixes to issues reported in previous Platform Previews."

IE9 Platform Preview 4 also supports modern Scalable Vector Graphics (SVG), improved WebKit SunSpider JavaScript benchmark results and an Acid3 test score of 95 out of 100. That is up from 83 out of 100 in IE9 Platform Preview 3.

With this preview, Microsoft also contributed 519 new tests to standards bodies, which brings the total number of tests contributed during IE9 development to 2,138.

The IE9 Platform Preview 4 can be downloaded here.

Hachamovitch closed out his post with advice for users on how to prepare for the IE9 beta. Said Hachamovitch:

"With the fourth Platform Preview, we strongly recommend developers, designers and partners to start getting your sites ready for the IE9 Beta.

  • Test your site in IE9 Standards Mode. This mode provides the best performance and interoperability and will offer additional benefits in the IE9 Beta. We suggest using the HTML5 doctype. More details here and here.
  • We recommend sending IE9 the same standards-based markup your site sends other browsers. More details here and here. From the feedback so far, and our experience with sites, the best way to get your site working in IE9 Standards Mode is to start from the same markup other browsers receive rather than IE6, IE7 or IE8 markup.
  • Use feature detection, not browser detection to handle any cross browser differences in behavior or feature support. This keeps your site working even as browsers change.
  • Please continue to report issues on Connect if your site doesn't look or work right, and you're giving it the same code as you're giving to other modern browsers. With IE9 Platform Preview 4, we've fixed over 100 community-reported issues. We will fix even more between now and the IE9 beta and want your feedback.
  • Consider the experience for IE9 Beta users if you find that sending the same markup creates more issues than you can resolve in your production site. It is possible that running your site in Compatibility View is better for your users.
  • Take advantage of HTML5, CSS3, SVG, DOM, ES5 and more ... all described here in the developer guide. We're excited to run the amazing experiences you bring to the web using these new capabilities, taking advantage of hardware through IE9."