【求助】关于html2canvas的问题


<!DOCTYPE html>
<html>
<head>
    <title></title>
    <script src="../build/html2canvas.js"></script>
    <script src="../build/jquery-1.9.1.min.js"></script>
</head>
<body>
<div style="color: red">kk3k</div>
<div style="color: green">kk3k</div>
<div style="color: blue">kk3k</div>
<input type="button" value="copy" id="bt">
<input type="button" value="copyimg" id="btimg">
</body>
<script>
    $(function(){
       $('#bt').click(function(){
          html2canvas(document.body,{
              onrendered:function(canvas){
                  document.body.appendChild(canvas);
              }
          })
       });
    $('#bt').click(function(){
          html2canvas(document.body,{
              onrendered:function(canvas){
                  var url = canvas.toDataURL();
                  var img = document.createElement('img');
                  img.src = url;
                  document.body.appendChild(img);
              }
          })
       });
    });
</script>
</html>
测试成功的代码  可以断点进入onrendered