html2canvas($targetElem, {
     useCORS: true,
     onrendered: function(canvas) {
     }
     });

 var nodesToRecover = [];
 var nodesToRemove = [];
 var $svgElem = $targetElem.find('svg');
 $svgElem.each(function(index, node) {
   var parentNode = node.parentNode;
   var canvas = document.createElement('canvas');

   canvg(canvas, parentNode, {ignoreMouse: true, ignoreAnimation: true});

   //将svg转换成canvas
   nodesToRecover.push({
      parent: parentNode,
      child: node
   });
   parentNode.removeChild(node);

   nodesToRemove.push({
      parent: parentNode,
      child: canvas
    });

    parentNode.appendChild(canvas);
 });
 html2canvas($targetElem, {
   useCORS: true,
   onrendered: function(canvas) {
      var base64Image = canvas.toDataURL('image/png').substring(22);

      //回复svg
      nodesToRemove.forEach(function(pair) {
          pair.parent.removeChild(pair.child);
      });

      nodesToRecover.forEach(function(pair) {
          pair.parent.appendChild(pair.child);
      });
   })