I was playing around with Cloud9 and reconstructed the magnifying glass demo on it. It has three files, one for html, one for css, and one for javascript. You can see it here: https://c9.io/russabbott/magnifying_glass. (I couldn't get there using IE, but Chrome and Firefox seemed to work.)

In playing around with it I noticed that if the width of the .magnify div and the width of the img are different the glass doesn't appear and disappear properly. See the Javascript for a comment about why.

-- Russ Abbott