title: Trying to black out everything outside of a moveable div
body: <p>I wrote a hover zoom plugin and I'm trying to figure out how to dark out everything outside of the hover zoom box, and make the zoom box itself transparent, but am having a tough time trying to figure out what I need to do for it. Do I use opacity? Do I use a background image?</p>
  
  <p>Right now it's just showing a white .5 opacity on top of a darker black opacity bg, but I'm kinda scratching my head trying to figure this out. Any suggestions would be super helpful.</p>
  
  <p>What I'm trying to do:</p>
  
  <p><img src="https://i.stack.imgur.com/7XGCR.png" alt="enter image description here"></p>
  
  <p>Demo: <a href="http://jsfiddle.net/someprimetime/9bsmt/46" rel="noreferrer">jsfiddle</a></p>