title: Highlight a section of an image in JavaScript
body: <p>I run a small webpage that allows users to click on various links using image maps.  I'd like to highlight the section that a user clicks on to give some feedback to the user (they may be clicking on several different parts rapidly).  </p>
  
  <p>Is there a way I can invert (or otherwise highlight) a small section of an image JavaScript?</p>