MooTools Overlay Plugin from David Walsh

David Walsh has created his own overlay effect using MooTools JavaScript. The overlays have become a big part of modern websites; we can probably attribute that to the numerous lightboxes that use them. He has found a ton of overlay code snippets out there but none of them satisfy my taste in code. Many of them are bloated, inflexible, or nonfunctional. The only way to make myself happy was to create one of my own.