title: Take screenshot of the whole webpage
body: <p>Need a working code with only javascript and no extra library files (-> jquery,...)
  That take a screenshot from the whole webpage. (top to bottom page)</p>
  
  <p>Current i have this which does not work why?</p>
  
  <pre><code>&lt;script type="text/javascript"&gt;
  document.addEventListener('DOMContentLoaded', function () {
  
  var window = document.getElementById('item');
  var canvas = document.getElementById('my-canvas');
  var ctx = canvas.getContext("2D");
  ctx.drawImage(window, 0,0, 100, 200, "rgb(255,255,255)");
  canvas.toDataURL("image/png");
  
  });
  &lt;/script&gt;
  &lt;/head&gt;
  &lt;body id="item"&gt;
  test website
  &lt;canvas id='my-canvas'&gt;&lt;/canvas&gt;
  </code></pre>