Extensibility improvements in IE8

This post discuss the improvements to extensibility model in Internet Explorer 8 RC1. Since IE8 Beta 1, the name of the Feature Control Key that is used to toggle that behavior is changed: previously called FEATURE_NATIVE_DOCUMENT_MODE. IE8 now refers to it by the key FEATURE_BROWSER_EMULATION, and the values for both IE7 Standards Mode and IE8 Standards Mode have changed.

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