title: Capture only current viewport not whole body as screenshot
body: <p>I'm using html2canvas to capture a screenshot of a site on different devices and send them to a storage via a XMLHTTPRequest. </p>
  
  <p>Especially on sites with a lot of content the resulting screenshots tend to be very high and large, although most of the information in the screenshot is not relevant to what I need to caputure.</p>
  
  <p>I've been trying to temper with the canvas element to have it only contain what I am currently seeing in the browser instead of capturing the whole body of the page, but without success. </p>
  
  <p>Is it possible to tweak html2canvas in a way that allows to only capture the current window instead of the whole body?</p>
  
  <p>Currently used code is:</p>
  
  <pre><code>html2canvas(document.body).then(function(canvas) {
          var img = canvas.toDataURL("image/png");
          ajax_post(img); 
      });
  </code></pre>