AsposePdfAddAttachment

function AsposePdfAddAttachment(
    fileBlob,
    fileName,
    fileAttachment,
    fileDescription,
    fileNameResult 
)

  /*Create Web Worker*/
  const AsposePDFWebWorker = new Worker("AsposePDFforJS.js");
  AsposePDFWebWorker.onerror = evt => console.log(`Error from Web Worker: ${evt.message}`);
  AsposePDFWebWorker.onmessage = evt => document.getElementById('output').textContent = 
    (evt.data == 'ready') ? 'loaded!' :
      (evt.data.json.errorCode == 0) ? `Result:\n${(evt.data.operation == 'AsposePdfPrepare') ? 'attachment prepared!': DownloadFile(evt.data.json.fileNameResult, "application/pdf", evt.data.params[0])}` : `Error: ${evt.data.json.errorText}`;

  var fileAttachment;

  /*Event handler*/
  const ffileAddAttachment = e => {
    const file_reader = new FileReader();
    file_reader.onload = event => {
      /*Add attachment to a PDF-file and save the "ResultPdfAddAttachment.pdf" - Ask Web Worker*/
      AsposePDFWebWorker.postMessage({ "operation": 'AsposePdfAddAttachment', "params": [event.target.result, e.target.files[0].name, fileAttachment, 'Description', "ResultPdfAddAttachment.pdf"] }, [event.target.result]);
    };
    file_reader.readAsArrayBuffer(e.target.files[0]);
  };

  const ffileAttachment = e => {
    const file_reader = new FileReader();
    /*Set attachment's filename*/
    fileAttachment = e.target.files[0].name;
    file_reader.onload = event => {
      /*Save the BLOB in the Memory FS for processing*/
      AsposePDFWebWorker.postMessage({ "operation": 'AsposePdfPrepare', "params": [event.target.result, e.target.files[0].name] }, [event.target.result]);
    };
    file_reader.readAsArrayBuffer(e.target.files[0]);
  };

  /*Make a link to download the result file*/
  const DownloadFile = (filename, mime, content) => {
      mime = mime || "application/octet-stream";
      var link = document.createElement("a"); 
      link.href = URL.createObjectURL(new Blob([content], {type: mime}));
      link.download = filename;
      link.innerHTML = "Click here to download the file " + filename;
      document.body.appendChild(link); 
      document.body.appendChild(document.createElement("br"));
      return filename;
    }

  var fileAttachment;

  var ffileAttachment = function (e) {
    const file_reader = new FileReader();
    /*Set attachment's filename*/
    fileAttachment = e.target.files[0].name;
    file_reader.onload = (event) => {
      /*Save the BLOB in the Memory FS for processing*/
      AsposePdfPrepare(event.target.result, fileAttachment);
    };
    file_reader.readAsArrayBuffer(e.target.files[0]);
  };

  var ffileAddAttachment = function (e) {
    const file_reader = new FileReader();
    file_reader.onload = (event) => {
      /*Add attachment to a PDF-file and save the "ResultPdfAddAttachment.pdf"*/
      const json = AsposePdfAddAttachment(event.target.result, e.target.files[0].name, fileAttachment, 'Description', "ResultPdfAddAttachment.pdf");
      if (json.errorCode == 0) document.getElementById('output').textContent = json.fileNameResult;
      else document.getElementById('output').textContent = json.errorText;
      /*Make a link to download the result file*/
      DownloadFile(json.fileNameResult, "application/pdf");
    };
    file_reader.readAsArrayBuffer(e.target.files[0]);
  };