Microsoft released this week a new test version of its Internet Explorer (IE) 10 browser that is bundled with Windows 8: Platform Preview 3 (PP3).
Like previously released Platform Preview builds, the IE 10 PP3 is aimed at developers, not end user customers.
PP3 is accessible in Windows 8 in two ways: As a "Metro style" application and a Microsoft Desktop App, i.e., one that is part of the classic/legacy mode of Windows 8. ("Metro style" refers to an app that is designed to take advantage of the new tile user interface and supporting operating-system infrastructure in Windows 8.)
The Metro IE 10 PP3 release does not support any browser plug-ins and extensions -- including Adobe Flash and Microsoft Silverlight. But Desktop App IE 10 PP3 does allow plug-ins and extensions.
Windows Chief Steven Sinofsky explained the distinction in a blog post this week. From that post:
"In Windows 8, IE 10 is available as a Metro style app and as a desktop app. The desktop app continues to fully support all plug-ins and extensions. The HTML5 and script engines are identical and you can easily switch between the different frame windows if you’d like."
The Metro version of IE 10, because it doesn't support plug-ins and extensions, "improves battery life as well as security, reliability, and privacy for consumers," according to the blog post.
Microsoft is advising Windows 8 customers who need to access consumer sites and line of business applications that require legacy ActiveX controls to use IE 10 in the Desktop App to get to these sites.
Microsoft did not update this week the IE 10 test build that works on Windows 7 and Windows Vista. That version of IE 10 is still at the PP2 milestone. Microsoft officials said that an a PP3 update for Vista and Windows 7 users would be released "at a future date." (Note: We don't know whether or not the next update is going to be PP3 for the standalone version of IE, and Microsoft is not saying.)
The PP3 version IE10 includes support for CSS Text Shadow, CSS 3D Transforms, CSS3 Transitions and Animations, CSS3 Gradient, SVG Filter Effects, HTML5 Forms and more. It also supports better offline application support via local storage with IndexedDB and the HTML5 Application Cache, as well as Web Sockets, HTML5 History, Async scripts, HTML5 File APIs, HTML5 Drag-drop, HTML5 Sandboxing, Web workers, ES5 Strict mode support.
Microsoft also updated its IE Test Drive site, as of this week, to be "touch-friendly," and added some new multi-touchable demos like Particle Acceleration, Lasso Birds, and Touch Effects.
Update: Adobe issued a statement on September 15 about its plans for Windows 8 on the Metro side of the house. "We expect Flash based apps will come to Metro via Adobe AIR, much the way they are on Android, iOS and BlackBerry Tablet OS today," according to the company statement.