The Platform Preview is an early look at the Internet Explorer 9 platform so some features are incomplete, some may change, and some may be added.

Internet Explorer Platform Preview is not a full web browser. It’s intended to give Web developers an early look at the Web platform technology coming in the next release of Internet Explorer.

Internet Explorer Platform Preview requires Windows 7 (x86 or x64) or Windows Vista SP2 (x86 or x64). Vista users must install Internet Explorer 8 or later to use the Platform Preview.

Release notes

Internet Explorer 9 Platform Preview