title: Cannot use getActiveObject() in Fabric.js
body: <p>I want to check the image quality of the selected image on canvas.</p>
  
  <p>My following code:</p>
  
  <pre><code>var canvas = $(".canvas-container").children('canvas').get(0);
  //console.log(canvas.getActiveObject().get('type'));
  console.log(canvas);
  </code></pre>
  
  <p>The getActiveObject() log gives an error:
   undefined is not a function.</p>
  
  <p>The other log returns:</p>
  
  <pre><code>&lt;canvas class="lower-canvas" width="850" height="230" style="position: absolute; width: 850px; height: 230px; left: 0px; top: 0px; -webkit-user-select: none;"&gt;&lt;/canvas&gt;
  </code></pre>
  
  <p>The canvas is created in another js file:</p>
  
  <pre><code>      //create fabric stage
          var canvas = $productStage.children('canvas').get(0);
  
          stage = new fabric.Canvas(canvas, {
              selection: false,
              hoverCursor: 'pointer',
              rotationCursor: 'default',
              controlsAboveOverlay: true,
              centeredScaling: true
          });
  </code></pre>
  
  <p>What must I change so I can use so I can use canvas.getActiveObject()?</p>
  
  <p>See <a href="http://www.panel-it.eu/shop/straatnaambord-3/#" rel="nofollow">http://www.panel-it.eu/shop/straatnaambord-3/#</a> for reference.</p>
  
  <p>Thanks in advance.</p>