News

Microsoft Releases IE 10 Platform Preview 4

• By Kurt Mackie
• November 22, 2011

The fourth platform preview version of Internet Explorer 10 was released by Microsoft today.

Microsoft today released the fourth version of its Internet Explorer 10 platform preview Web browser prototype.

The previous release, platform preview 3, was bundled up with the debut of the Windows 8 developer preview operating system, which appeared at the Microsoft Build conference in mid-September. Microsoft's platform preview releases seem to occur whenever the development team is seeking feedback on browser features, rather than according to a fixed schedule.

In order to test platform preview 4, users have to have Windows 8 developer preview installed, which can be accessed here. Platform preview 4 won't run on Windows 7, although the final browser product will be designed to run on both operating systems. Platform preview 2 apparently was the last release that ran on its own, not requiring Windows 8.

The new platform preview 4 adds some CSS 3, HTML 5 and DOM changes for developers to test, according to Microsoft's revision history. However, Microsoft's IE blog is a bit more descriptive. One of the improvements involves cross-origin resource sharing (CORS) technology. CORS facilitates file sharing across domains using the XMLHttpRequest method. A demo shows how CORS can be used to transfer files by dropping them onto a graphic.

Another improvement in IE 10 platform preview 4 is new support for text captions in HTML 5-encoded video streams. Microsoft describes this improvement as "track captioning." Track-captioned text can contain links, allowing users to click and move through a video, Microsoft explained in the IE blog.

Developers can control which text at their Web sites is selectable by users. Microsoft describes this feature in platform preview 4 as "CSS user select support."

Microsoft updated its quirks mode in IE 10 platform preview to work more like the quirks mode found in other browsers, such as Chrome, Firefox, Safari and Opera.

Microsoft also claims it has speeded up performance in IE 10 when combining the canvas element, gradients and opacity, scalable vector graphics rendering, and hardware acceleration. A demo showing a cityscape with falling raindrops formed through CSS transforms generated visuals at 60 frames per second in the IE 10 platform preview 4 vs. three to four frames per second when running on Google Chrome.

Microsoft claims that these improvements in the IE 10 platform preview 4 will apply not just to the Web pages parsed through company's nascent browser, but they also apply to Metro-style applications running on Windows 8.

"The features in this platform preview are available to Web pages now, and will be available to Metro style applications in Windows 8," Microsoft states in its IE blog.

Platform preview 4 of IE 10 can be downloaded at Microsoft's test-drive page here. A guide for developers can be accessed at this page.