rollover

A technique when using JavaScript, allows for an alternate image to be displayed when the mouse rolls over a specific line of text or graphic on the Web page. The "rollover" typically displays a copyright notice on top of the image. If the user attempts to capture the image using the right click "save image as" option, the alternate image (such as the copyright) is captured instead. The term rollover was created to recognize that there is a little ball in your mouse that you roll on a surface.