Check my Gumroad page for commented source code, games and books. You may call it Lightbox, or Greybox, or Thickbox, but it’s always the same effect. When you are on a page, and click on a photo or trig some event, a Lightbox is an effect that fades the pagein the background to show you new content in the foreground. I mean this effect In the upper example, when clicking on a photo the site fades
