* Addition of the CSS user-select property to control how end-users select elements in a Web page or application.
* Support for HTML5 video text captioning, including time-code, placement, and captioning file formats.
* Support for CORS (cross origin resource sharing), which allows developers to use XMLHttpRequest to request, share and move data across applications on different domains.
IE10 PP4 also introduces an updated quirks mode "that is more consistent and interoperable with the way quirks modes works in other browsers like Firefox, Chrome, Safari, and Opera," according to today's post.
"The features in this platform preview are available to Web pages now, and will be available to Metro style applications in Windows 8," said Rob Mauceri, Group Program Manager and author of the blog post.
IE10 is expected to be available for Windows 7 and to be integrated with Windows 8. Microsoft is believed to be aiming to release IE10 shortly before or at the same time it releases to manufacturing Windows 8, which Microsoft watchers believe will be around mid-2012.