title: Canvas.toDataURL() Uncaught TypeError: undefined is not a function
body: <p>I'm using a plugin called html2canvas to convert some html on my page into a canvas element. I then want to save that canvas as an image. Unfortunately I keep encountering the error in the title. I have tried with different variable names, with different html, etc. But keep encountering the same error. Here is my code (triggered on a button click):</p>
  
  <h2>JS</h2>
  
  <pre class="lang-js prettyprint-override"><code>function generate(){
          html2canvas($('#b2_1'), {
              onrendered: function(canvas) {
                  canvas.setAttribute("id", "canvas");
                  document.body.appendChild(canvas);
              }
          });//this all works, the canvas appears as expected
  
          var myCanvas = $(document).find('#canvas');
          myCanvas.css("margin-left", "50px");//this was to test I was selecting the right element, the canvas moves
          var myImg = myCanvas.toDataURL();//code breaks here
      }
  </code></pre>