The fourth preview of Internet Explorer 9 has been released to developers. Try out fully hardware-accelerated HTML5, try out modern SVG and see native JavaScript integration in action. The announcement was made on the IE blog at HTML5, Modernized: Fourth IE9 Platform Preview Available for Developers.

You can get the preview at IE 9 Platform Preview.

Developers should be testing your sites now and seeing how you can take advantage of the standards-based features.

New Features in IE9

Fully Hardware-Accelerated HTML5. IE9 offers consistent, fully hardware-accelerated text, graphics, and media, both audio and video. Try Hamster Dance Revolution, IE Beatz, or MSNBC Video in different browsers to experience the difference. Psychedelic Browsing demonstrates what HTML5 canvas can do when it’s fully accelerated with the GPU.

Modern SVG. With Platform Preview 4, you experience highly-interactive and integrated, or modern, SVG. Typically, developers think of SVG as the graphics format for static engineering diagrams and images. With HTML5 and hardware acceleration, SVG is an excellent choice for a new class of interactive, animated scenarios. You can see great SVG performance, animated via JavaScript, with the SVG Dice example.

Native JavaScript Integration. One aspect of doing these things well is integrating the JavaScript engine natively inside the browser, rather than bolting it onto the side to support multiple JavaScript engines as some other browsers do today.With this change, communication between the browser and script engine is now direct, which significantly improves performance for real world websites.

Standards Support

To assess the quality and completeness of a browser’s standards support, we look to the official standards bodies. Their open, consensus-based process is the best way to bring the community of browser vendors and web developer and design professionals together in building a test suite.

With Platform Preview 4, we’re contributing 519 new tests to the standards bodies. Based on community feedback, we’ve also updated five of the previously submitted tests. This brings the total number of tests we’ve contributed during IE9 development to 2,138.

Getting Ready for IE9

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 Microsoft 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.

For deeper dive into the features, see HTML5, Modernized: Fourth IE9 Platform Preview Available for Developers.

Roadmap

Platform Preview 4 is an important milestone on the way to beta. It is the last preview before the IE9 Beta becomes available in September.

Bruce D. Kyle
ISV Architect Evangelist | Microsoft Corporation