Microsoft has released the IE10 Platform Preview 2, the same HTML5 engine seen in the recent public "Windows 8" demos. The browser is now available for download. With this update, IE10 continues to deliver support for site-ready HTML5 technologies as well as improving performance.

The new capabilities available in IE10 PP2 are going to allow developers to build interactive web applications with HTML5.

Microsoft claims that beautiful and interactive Web applications are easier to deliver with support for several new technologies like CSS3 Positioned Floats, HTML5 Drag-drop, File Reader API, Media Query Listeners and initial support for HTML5 Forms.

For example, IE10 supports CSS3 Positioned Floats to enable text flows around figures on a page, building on the first Platform Preview?s support for CSS3 grid, multi-column, and flexbox:



This IE10 Platform Preview also includes parsing improvements from the W3C HTML5 spec, reflecting that developers can now expect the same behavior in all compliant browsers even for imperfect or invalid markup. HTML5 is the first version of HTML to define the behavior of invalid markup. Rather than relying on "fix-up" rules that vary from browser to browser, HTML5 parsing behavior is now specified in a way that developers can count on it. IE10 now supports the File Reader API and HTML5 Forms validation, as well as advanced hit testing for more complex selection scenarios like graphics editors, games, and other applications that typically use multiple graphics layers.

IE10 is also the first browser to support several new performance APIs coming out of the W3C's working groups. The test drives for setImmediate, requestAnimationFrame, and PageVisibility illustrate how these APIs enable developers to make the Web faster and more responsive even while Web sites make better use of battery life on mobile devices.

One of the more interesting things is how a number of the new technologies in PP2, like Web Workers with Channel Messaging and Async script support, will do even more with IE to make it efficient when it comes to battery life.

Web workers enable a host of new programming scenarios for the Web. With them, Web applications can be more responsive by offloading complex JavaScript to run in the background. For example, casual games might choose to run the logic for the "computer player" in a Web worker while users take their turn. This test drive demonstrates the performance benefit of offloading work from the page to a Web worker.

With support for Async script, developers can control the impact on Web page performance of their scripts downloading from their sites.

This IE10 Platform Preview also supports HTML5 Sandbox and iframe isolation, an important component to Web application security:



Developers can test out these newly supported standards today at www.ietestdrive.com with demos like Fireflies, which highlights HTML5 canvas, audio, video and CSS gradients all coming together. The importance of hardware accelerating all the graphics, audio, and text is becoming increasingly evident as developers work across technologies to deliver compelling sites.