IsoView WebCGM attaching events to hotspots

how can I attach an event to a hotspot via javascript, so when it's clicked i can return its index name?

I have the object written as such:

<object id="webcgm" type="image/cgm;Version=4;ProfileId=WebCGM" name="webcgm_name" width="100%" height="100%">
<param name="src" value="../figure/image.cgm"></param>
</object>

This graphics already contains several hotspots.