Wow! When I saw "image map" on the title I thought this can't actually be talking about the HTML image map. Image map reminds me of HTML from the late 90s, and give me a good nostalgia of making personal homepages from that time. With invisible clickable divs, absolute positioning css and what not, it seems like image map has become a thing of the past. I'm guessing the requirement of making it work with no JS took you to the path of using image maps. Neat technique.