Fun with highlights

Image Appears When Text Is Highlighted

Try selecting the innocent-looking text over at this page using Firefox.

Spoiler: What happens is that you can see the word "Google" appear. This hack utilizes the CSS3 "selection" pseudo-element. Each portion of letters in the HTML receives its own class, like foo. Stylesheet definitions like the following handle the rest:

  ...
.color-51::selection {
 color: rgb(79, 106, 115);
 background: rgb(79, 106, 115)
}
.color-51::-moz-selection {
 color: rgb(79, 106, 115);
 background: rgb(79, 106, 115)
}
...

A tool to create your own selectable text this way is available, too.

Via