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Microsoft Starting New IE 10 Flash Policy This Month

Microsoft gave a one-day advance notice today that it will enable the Adobe Flash Player "to run by default" in Internet Explorer 10, starting on March 12.

The announcement by Rob Mauceri, group program manager for Internet Explorer at Microsoft, is a bit confusing because Flash can still be blocked -- even by Microsoft itself. What apparently has changed is Microsoft's procedures associated with IE 10's "compatibility view" (CV) list, which specifies how a Web site's code should be handled.

A Microsoft developer guidance publication on Flash and IE 10 in Windows 8 explains how the CV list operated, and what will change on Tuesday.

"When first released, Internet Explorer 10 used the CV List for Flash to identify sites that were allowed to run Flash content," the guide explains. "As of March 2013, Internet Explorer 10 uses the CV List for Flash to block Flash content for specific websites. This behavior change requires Internet Explorer 10 to be fully patched with all available security updates."

Starting on March 12, the CV list will just lists sites where Flash content should be blocked. This Flash-blocking action just happens for IE 10 on Windows 8's "Windows Store apps" user interface side (formerly known as the "Metro" side). The "Desktop" user interface side of Windows 8 can still play Flash or any other IE 10 browser add-in.

On the Windows RT side, things are a bit different. In those cases, a Web site listed in the CV list won't play Flash at all.

"For Windows RT, sites that are on the CV list for Flash cannot play Flash content in either Internet Explorer for the desktop or Internet Explorer in the Windows UI," Microsoft's IE 10 guide states. There was no explanation for this disparity between Windows 8 and Windows RT.

Microsoft controls which sites get on the CV list. Developers can add a line of code to their sites that will push visitors to the site to use the Desktop side of IE 10 on Windows 8 machines, but the CV list itself is controlled (or "curated") by Microsoft itself. If a developer, IT pro or content provider doesn't want their site on Microsoft's CV list, then they have to send Microsoft an e-mail. The e-mail has to include seven pieces of information, as specified in Microsoft guidance publication. Microsoft will get to the request in about six weeks, and either accept or reject the request. If the removal request is accepted, Microsoft still needs to update the CV list, which happens about once a month.

So, in essence, Microsoft is still taking an active part in policing the performance of Web sites with Flash, but the CV List now is used for blocking Flash (black list), rather than as a white list for Flash sites. Microsoft took this approach even though it has found that only a small number of sites aren't compatible with IE 10 on Windows 8 and Flash.

"Of the thousands of domains tested for Flash compatibility to date, we have found fewer than 4% are still incompatible, in the most part because the core site experience requires other ActiveX controls in addition to Flash," Mauceri wrote.

One of those ActiveX add-ins is Microsoft's own Silverlight, it seems. Many readers of Microsoft's announcement added comments wondering about whether Microsoft would allow support for Silverlight, which supports multimedia playback in browsers as an alternative to Flash. Silverlight still runs on the Desktop side of Windows 8 in IE 10, but it has entirely lost its luster for IE 10 running on Windows RT.

"Silverlight runs in Internet Explorer 10 for the desktop on Windows 8," a Microsoft spokesperson explained. "Silverlight will not be supported in immersive Internet Explorer 10 since these capabilities are superseded by the new WinRT API."

Microsoft apparently took this firm hand on controlling the Flash experience because it wants to ensure the quality of the touch experience of IE 10 on Windows 8 and Windows RT. So it worked with Adobe to add the Adobe Flash Player to Windows 8 and Windows RT. It's the same Flash Player used across the two interfaces of those two operating systems, Microsoft has explained.

Microsoft's announcement pointed to its development guidance publication for "a best practices guide to help developers, designers, and content publishers create experiences with Flash that play well in IE for touch, responsiveness, and battery life." There's also a Microsoft Web portal, called "modern.IE," that offers testing tools for Web sites, although the text box for a URL scan at that portal doesn't seem to work.

About the Author

Kurt Mackie is senior news producer for the 1105 Enterprise Computing Group.

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