A Lightbox is a piece of JavaScript used to display images and videos in an ‘overlay’.
Basically, a user can click on an image to either have the image – or a video – magnified in a Lightbox window. It is usually accompanied by the use of a dark background, usually a dimming of the page over which the image or video has been overlaid, which helps highlight the image or video being displayed.
For example, click on the image below, and see what happens.
And you can see it in action, on a real, live web site, at the home page of http://DigitalAccessPass.com
This Lightbox script is available for free. It is actually open-source, and released under the MIT license – which means you can also use it in commercial projects.