Just built a pretty significant business application with a UI based on HTML5 drag and drop. There were certainly a few quirks, but it was nothing compared to

Just built a pretty significant business application with a UI based on HTML5 drag and drop. There were certainly a few quirks, but it was nothing compared to web development in "the old days". Without any library the whole DnD song and dance is implemented as part of a React component that's only about 100 lines of JavaScript. There are two places likely to trip you up. One of them is as mentioned in the original article: it's hard to remember which events need to have their default prevented. At the moment we're calling `preventDefault` in `onDragOver` which is required to identify the element as a drop target, and `stopPropagation` in `onDrop` which I believe is to prevent many browsers' default attempts to navigate to a dropped url-like thing. The other potential pitfall is that, for security reasons, the data can only be read in `onDrop`, not in `onDragOver`. If you have a string id you don't mind being downcased you can just use the hack of sending that through the data transfer types (eg. as type "id/12345"), with a "text/plain" fallback.