HTML5 Canvas eraser

Question

There's a way of implementing an eraser (other than using a white pencil?).

I'm using layering, I have an image below the canvas, so, if eraser paints white, the user is going to notice since the below image isn't solid white.

Answer 1

https://developer.mozilla.org/en-US/docs/Web/API/Canvas_API/Tutorial/Compositing

Actually the function is:

function eraser(){
    context.globalCompositeOperation = "destination-out";  
    context.strokeStyle = "rgba(255,255,255,1)";
}

And you can go back to source-over.