It seems that each of the various drag and drop event handlers only know about either the object being dragged, or the area into which it’s being dropped. Not both. This means that when dropping an object its receiver can’t know what’s arriving.
There is a dataTransfer object that can be seen by both ends, which [...]

Spend a few hours this afternoon playing with drag and drop in IE.
There seems to be two main approaches. At JavaScriptKit they use onmousedown and onemouseup to grab elements with class=draggable and then dynamically change their x/y position.
This creates a better visual effect than the official Microsoft approach, which uses a variety of new eventhandlers. [...]