The latest Dojo download, version 1.6, has just been released. Included is a completely new, HTML5 multi-file uploader, a widget that creates a stylable file-input button, with optional multi-file selection, using only HTML elements. Non-HTML5 browsers have fallback options of Flash or an iframe.
The dojox.form.Uploader is an improvement upon, and replaces the dojox.form.FileUploader. The various problems created by Flash are avoided because it is not used in Mozilla and Webkit browsers. Support for FileUploader will cease as of 1.6, but the code will remain until 2.0 for backwards compatibility.