title: html2canvas missing background
body: <p>I am using html2canvas to generate image from my html page.</p>
  
  <p>When I enter my url
  <a href="http://prompter.rareapps.org/prompt/prompt-save2.php?p=123" rel="nofollow">http://prompter.rareapps.org/prompt/prompt-save2.php?p=123</a></p>
  
  <p>in webpage renderer of html2canvas website (<a href="http://html2canvas.hertzen.com/screenshots.html" rel="nofollow">http://html2canvas.hertzen.com/screenshots.html</a>) my page is rendered corectly with background.</p>
  
  <p>But when I generate my own canvas, I do not have the background. Here is my code</p>
  
  <pre><code>&lt;script type="text/javascript"&gt;
  $( document ).ready(function() {
      html2canvas(document.body, {
          allowTaint: true,
          taintTest: false,
          onrendered: function(canvas) {
          window.location.href = canvas.toDataURL('image/jpeg');
        }
      });
  });
  </code></pre>
  
  <p>What did I miss?</p>
  
  <p>Thanks</p>