https://codepen.io/akshgods/pen/opmjLg

.js

 $("#pix-qrcode .button").click(function () {
  var value = $("#getpix").val();
  var $temp = $("<input>");
  $("body").append($temp);
  $temp.val(value).select();
  document.execCommand("copy");
  $temp.remove();
});