qrcode 生成二维码并下载dataUrl到文件

function downloadURI(uri, name) {
  var link = document.createElement("a");
  link.download = name;
  link.href = uri;
  document.body.appendChild(link);
  link.click();
  document.body.removeChild(link);
  delete link;
};

window.onload = function ()
{
  console.log(‘onload‘);
  let qrcode = new QRCode(document.getElementById("qrcode"),
             {
              text: "http://www.runoob.com",
              width: 450,
              height: 450,
              colorDark : "#000000",
              colorLight : "#ffffff",
              correctLevel : QRCode.CorrectLevel.H
            });  
  setTimeout(
    function ()
    {
        let dataUrl = document.querySelector(‘#qrcode‘).querySelector(‘img‘).src;
        downloadURI(dataUrl, ‘qrcode.png‘);
    }
    ,1000);

};