<div id="code"></div>

<img id="img"/>

<script type="text/javascript">

  var qrcode=$("#code").qrcode({

    render:'canvas||table',

    width: 200, //宽度

    height:200, //高度

    text: "http://www.baidu.com" //任意内容

  }).hide();

  var canvas=qrcode.find('canvas').get(0);

  //如果有循环,此句必不可少 qrcode.find('canvas').remove();

  var data = canvas.toDataURL('image/jpg');

  $('#img').attr('src',data) ;

  saveFile(data,"fd范德萨范德萨");

  //转为图片的方法,需要上门的data

  function saveFile(data,filename){

    var save_link=document.createElementNS('http://www.w3.org/1999/xhtml', 'a');

    save_link.href=data;

    save_link.download=filename;

    var event=document.createEvent('MouseEvents');

    event.initMouseEvent('click',true,false,window,0,0,0,0,0,false,false,false,false,0,null);

    save_link.dispatchEvent(event);

  };

</script>