This is only a representation of the actual Moon illusion, and is not the actual illusion itself. However it is a fairly accurate thumbnail of how the Moon might appear in the night sky.
In this demonstration the Moon will follow your mouse from low on the horizon to a point high in the sky. The Moon will grow to about one and a half times its normal size when it is near the horizon. This is how the Moon Illusion might look to an observer on the ground.
About 85% percent of the population can see this illusion in nature.