QRCode.js二维码生成并能长按识别

<div id="codeBox"> <div id="qrDiv" style="display: none;"></div> <div id="qrcode"></div> </div>

var user_id="" //用户IDuser_id=getQueryString('user_id'); //获取user_id参数var url= '' //请求url  $(function(){  //生成二维码  var downUrl=url+user_id;  var qrcode = new QRCode("qrDiv", {    text: utf16to8(Url),    render: "canvas", //渲染方式有table方式（IE兼容）和canvas方式    width: 128,    height: 128,    typeNumber:-1,//计算模式    colorDark : "#000000",   //前景色    colorLight : "#ffffff",   //背景色    correctLevel : QRCode.CorrectLevel.H   //容错级别  });  var mycanvas1=document.getElementsByTagName('canvas')[0];  //将转换后的img标签插入到html中   var img=convertCanvasToImage(mycanvas1);    $('#qrcode').append(img);//imagQrDiv表示你要插入的容器id      })  //从 canvas 提取图片 image   function convertCanvasToImage(canvas) {   //新Image对象，可以理解为DOM   var image = new Image();   // canvas.toDataURL 返回的是一串Base64编码的URL，当然,浏览器自己肯定支持     // 指定格式 PNG   image.src = canvas.toDataURL("image/png");     return image;   }   //获取请求参数值  function getQueryString(name) {  var reg = new RegExp('(^|&)' + name + '=([^&]*)(&|$)', 'i');  var r = window.location.search.substr(1).match(reg);  if (r != null) {    return unescape(r[2]);  }  return null;    }  //中文编码格式转换  function utf16to8(str) {    var out, i, len, c;    out = "";    len = str.length;    for (i = 0; i < len; i++) {      c = str.charCodeAt(i);      if ((c >= 0x0001) && (c <= 0x007F)) {        out += str.charAt(i);      } else if (c > 0x07FF) {        out += String.fromCharCode(0xE0 | ((c >> 12) & 0x0F));        out += String.fromCharCode(0x80 | ((c >> 6) & 0x3F));        out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));      } else {        out += String.fromCharCode(0xC0 | ((c >> 6) & 0x1F));        out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));      }    }    return out;  }