In my XUL I have the following code fragments:
<map name="KeypadMap">
<area href="javascript:pad('A')" coords="1,1,31,31" shape="rect"/>
</map>
...
<hbox flex="1">
<image src="./keypad.png" width="32" height="32" useMap="#KeypadMap"/>
</hbox>
The image displays just fine, however, when I mouse over, the cursor does not change to a hand, and clicking does not call the pad function.
Similar code works fine in straight HTML, so there must be some trick to get it working via a Firefox XUL file.