When drawing vector graphics in the canvas you set the fillStyle using an rgba string like this...
context.fillStyle = "rgba(255, 223, 191, 1)";
context.fillStyle = "rgba(255, 223, 191, " + alpha + ")";
The specification clearly says "a CSS Color string" but it seems crazy. Am I missing something?
update: I switched to using globalAlpha for this specific example. But still seems crazy.