The fourth preview of Internet Explorer 10 has just been released by Microsoft, bringing a host of HTML5-related improvements. This release is squarely focused on developers and brings little in the way of new consumer-facing features — in fact, you need to be a developer running the Windows 8 preview build to download the new IE preview. The biggest new feature is called Cross-Origin Resource Sharing (CORS), which allows web developers to upload and move data across different domains. Microsoft's example showed an HTML5 web app hosted on one domain that uploaded documents to another domain; as long as both domains are CORS-compliant, they can communicate and share data.
Another highlight of this new preview is drastically increased performance — Microsoft showed off an HTML5 demo running at 60fps in IE that only hit 4fps in the latest version of Chrome (though we're sure Google will have its own demos showing how forthcoming versions of Chrome are faster than IE 10). Other new additions include HTML5 video captioning and tools that enable developers to only allow text or image selection on designated parts of their web apps. If you're interested to see where Microsoft is taking the next Internet Explorer, there's a bunch of interactive demos over on the IE blog to try out.