An imagemap is just a set of coordinates that map a mouseover to an area in your map.
A quick google and I dont see any Drupal related imagemap modules. You could try to store coordinates as a field in your node. But, that sounds messy. An imagemap basically assumes a user has intimate knowledge of the image to properly build the coordinate sets.
onMouseOver
is a Javascript event. HTML, CSS, the HTTP protocol, Javascript all work together to power the internet nowadays; so of course you can use Javascript code in a Drupal website. Drupal is simply a PHP CMS making use of all these things ... So long as the client browser supports it -- you're fine.