Facebook is testing a new photo-uploading tool built entirely in JavaScript, CSS and HTML as an alternative to its current solution, which is based on ActiveX controls, Java applets and Flash, Inside Facebook reports.

Users can activate the new tool via Facebook’s Prototypes page.

Facebook engineer Chris Putnam told Inside Facebook:

The photos in thumbnail view are served by a lightweight local Web-server thread, while the file-system information is provided through a JavaScript API. After selecting photos and starting an upload, you’ll discover another great feature—asynchronous uploading. The plug-in spins off a background thread to perform the upload regardless of what the browser is doing in the foreground. Then the local Web server provides JSONP endpoints to retrieve progress information or cancel the ongoing upload, without needing to re-embed the plug-in itself. With this approach, you can even navigate away from Facebook entirely without worrying about your uploads.

Putnam added, “Depending on the results of these tests, we hope to roll it out to all users soon.”