File not downloading with BLOB object in iphone chrome browser

Combining with Mose Answer's above ,you can detect the os type and set your code accordingly to download

function hello(id) {
  //alert(id);

  //alert(id);
  var ln = "en";
  $.ajax({
    type: "post",
    url: "ajaxurl",
    data: { lang: ln, num_srno: id },
    success: function(data) {
      //alert(data);

      /*  var bytes = new Uint8Array(data); // pass your byte response to this constructor

    var blob=new Blob([bytes], {type: "application/pdf"});// change resultByte to bytes

    var link=document.createElement('a');
    link.href=window.URL.createObjectURL(blob);
    link.download="myFileName.pdf";
    link.click();*/
      var sampleArr = base64ToArrayBuffer(data);
      saveByteArray("Sample Report", sampleArr);
    }
  });
}

function base64ToArrayBuffer(base64) {
  var binaryString = window.atob(base64);
  var binaryLen = binaryString.length;
  var bytes = new Uint8Array(binaryLen);
  for (var i = 0; i < binaryLen; i++) {
    var ascii = binaryString.charCodeAt(i);
    bytes[i] = ascii;
  }
  return bytes;
}

function getMobileOperatingSystem() {
  var userAgent = navigator.userAgent || navigator.vendor || window.opera;

  // Windows Phone must come first because its UA also contains "Android"
  if (/windows phone/i.test(userAgent)) {
    return "Windows Phone";
  }

  if (/android/i.test(userAgent)) {
    return "Android";
  }

  // iOS detection from: http://stackoverflow.com/a/9039885/177710
  if (/iPad|iPhone|iPod/.test(userAgent) && !window.MSStream) {
    return "iOS";
  }

  return "unknown";
}

I hope it helps.

there are some issue on iOS's Chrome. In my case using FileReader() solved the problem:

var reader = new FileReader();
var out = new Blob([this.response], {type: 'application/pdf'});
reader.onload = function(e){
  window.location.href = reader.result;
}
reader.readAsDataURL(out);