Save/restore background area of HTML5 Canvas

Question

I am using HTML5 canvas as follows:

1. Display an image that fills the canvas area.
2. Display a black text label over the image.
3. On click of the t

Answer 1

function draw(e){
    ctx.drawImage(img, 0, 0);
    if(e){
        ctx.fillStyle='red';
        ctx.fillRect(5, 5, 50, 15);
        ctx.fillStyle='white';
    }else{
        ctx.fillStyle='black';
    }
    ctx.fillText('Label', 10, 17);
}
draw();
document.onclick=draw;