CSS or JavaScript to highlight certain area of image opacity

Question

I\'m looking to do something like this but with CSS or JavaScript.

I need to highlight a certain part of an image but everything I find is how to do it in Photoshop.

Answer 1

You can probably fake it, here is a sample: http://jsfiddle.net/erick/JMBFS/3/

I covered the image with an opaque element. The color of the element is the same as the background of the image. Used z-index to put it on top.