Can't move with scripts - HTML5

So I've been trying to create a game with Adobe

Animate and HTML5 canvas just for fun.

Anyways I can't seem to get player movement to work.

I've tried using:

var canvas = document.getElementById("canvas");
canvas.addEventListener("keydown", doKeyDown, true);
function doKeyDown(e) {
	var playerSpeed = 100;
	//W Key
	if (e.keyCode == 87) {
		this.player.y-=playerSpeed;
	}
	//S Key
	if (e.keyCode == 83) {
		this.player.y+=playerSpeed;
	}
	//A Key
	if (e.keyCode == 65) {
		this.player.x-=playerSpeed;
	}
	//D Key
	if (e.keyCode == 68) {
		this.player.x+=playerSpeed;
	}
}

 And it didn't work, so if you can help please do.

Thanks in advance.