HTML and CSS Reference
Step 3: Animate the UFOs
To create simple animation we're hiding and displaying one of two illustrations for each
UFO. SVG can create animation on its own, but using a CSS method is cleaner and less
processor-intensive when applicable. To finish your animation and helper methods for
build() , integrate the following listing into your UFO object.
Listing 7.22. game.js—UFO animation and helpers