FYI, unlike most new HTML5 standards which were discussed in the WHATWG list and added to the standard based on developers' needs, "HTML5" DnD is a standardizat

FYI, unlike most new HTML5 standards which were discussed in the WHATWG list and added to the standard based on developers' needs, "HTML5" DnD is a standardization of the bizarre implementation of Drag and Drop used by some web pages after Microsoft introduced as part of Internet Explorer 5 in 1999. Don't expect it to be a sane foundation for what you want to do.