title: How to get the background color of a canvas
body: <p>What I am trying to do is this:
  Using Fabricjs, I wish to <code>alert("the bg color is: "+canvas.getBackgroundColor())</code> however, that method does not exist. </p>
  
  <p>I also tried <code>canvas.backgroundColor</code> but that returns an empty string.</p>
  
  <p>Despite my efforts, nothing seems to return the background color of a canvas. Does anyone know how to do that?</p>