How to determine whether browser provides hardware acceleration for HTML5 Canvas

Is there any way to determine whether the browser is using hardware acceleration for the rendering of an HTML5 canvas? This would be us开发者_如何转开发eful for enabling/disabling certain expensive features.

Apparently, it's not possible.

It is possible. Start Safari with this command: CA_COLOR_OPAQUE=1 /Applications/Safari.app/Contents/MacOS/Safari