
It uses Google's jQuery & jQuery UI API, especially jQuery UI Draggable widget for item symbols. Instead of multiple layers of a single symbol like sst13's tool uses, this version has a single layer of an item symbol that gets cloned while dragging. This makes for a a theoretically infinite number of the same item on the page, whilst sst13's tool has a final maximum number of clones of the same item. You can download the template demo page from this link. The password is, as usual, kerberos. It's then easy to remake the demo page for your app needs. I'm going to make PHP dynamic version using a JSON map database.