This page tests whether or not the browser updates an image map after an area element has been changed by javascript.
The green square should always be aligned with an area element.

Click to move

Naively updating the coords attributes doesn't work in webkit browsers, but there is a work around:

1. Remove area node from the document
2. Clone area node
3. Update coords attribute
4. Reattach event listeners
5. Append clone to map element