In the webgl port of my engine, I've found that alpha textures brighten what is behind them. This is not the desired behavior and is different from what I'm getting in my OpenGL engine. I'm using...

gl.blendFunc ( gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA );

Is this a known bug or am I possibly forgetting something else that would affect the render? The shader is very straight-forward...