The World Wide Web Consortium has published a draft of an interface that browsers can use to manipulate files better, one of a series of steps aimed at gradually improving the sophistication and polish of Web site interfaces.

The draft File API (application programming interface) defines a number of ways that browsers and Web sites can handle files better. One big part of it: being able to select multiple files for upload, such as on photo-sharing sites or Web-based e-mail, a task that often relies on Adobe Systems’ Flash today.

But there are other aspects, too. For example, the Files interface governs the use of “blobs,” or packages of raw binary data such as video files. Google has touted blobs for its Gears browser plug-in as a way to divide large videos into small chunks so that uploads can be more easily resumed if a network problem interrupts the process.

Another benefit: files are handled asynchronously, which means the browser won’t freeze up while a file is being uploaded or otherwise handled, and the browser reports progress on file transfers.

Firefox 3.6, in beta testing now, will support most of the Files API, according to Blizzard.