Set variable within another context

I have the following function

"use strict";

function Player

{

    this.width;

    this.height;

    this.framesA = 5;



    this.image = new Image();

    this.image.onload = function ()

    {

        width = this.width;

        height = this.height / framesA;

    }

    this.image.src = "Images/angel.png";

}