Each canvas is initially transparent (hence appearing white), then a black triangle is drawn in the bottom-left; then globalCompositeOperation is set, and a green cross with a blurred offset blue shadow is filled.

The "per spec" column doesn't blur. It doesn't follow the spec in some versions of WebKit and Konqueror, so use Firefox or Opera.

Composite
operation
Without
shadows
With
shadows
Per spec
(2008-07-29)