CVI glossy.js uses the html5 canvas element. This element is already supported by most modern browsers. What canvas allows you to do is image processing on the browser side. What glossy script does is it takes any image, which has the class style of glossy, and goes through the steps that one would do in photoshop to create a glossy web 2.0 image or vista type button.
One thing this technology does is allows users to upload a graphic to their space and apply graphics processing to it provided by the site. Another thing it does is saves time by allowing whatever graphics steps that a web designer goes through for each graphic to be done instead by assigning a class to the image in the markup process.
As a current example I am using it on Sdfreelance
Note: for backwards compatibility glossy.js is using schemas-microsoft-com:vml not just canvas.