I did some researching of my own on the subject the HTML5 Drag and Drop feature and the HTML5 File API.
This doesn't look like something I can condense into the normal time-frame of creating a code-snippet based on pure HTML code, though it would be nice if I could.
Happily you can still contact Navot to the e-mail address specified earlier, and request that this will be implemented and fully tested for you by our development team.
I will personally be very happy to see this as an integrated component of the Visual WebGui framework.
Support Manager, the Visual WebGui team