Get excel file (.xlsx) from server response in ajax

Question

I have got a problem with getting excel file and opening download window in the browser after getting a response (in success ajax method) with that file. I have got appropriate Content-Type and Content-Disposition headers, I tried using Blob in js and I couldn't achieve what I want - simple file downloading.
I accomplished few versions of my ajax, one of them is below. I developed ajax which returns excel file which I couldn't open properly because it's corrupted (despite .xlsx extension).

Maybe the problem is with inappropriate data type used in Blob constructor?

I tried using "xhr.response" instead of "data" from success method arguments but it doesn't work too. I checked Response Headers in Developer Tools in Chrome and they are set properly.
The important thing - all the excel workbooks created on the server side is correct because it worked in the previous version when data was sent in URL, not in ajax post.

Controller method in Java/Spring server side below:

response.reset();
response.setContentType("application/vnd.ms-excel");
response.addHeader("Content-Disposition","attachment;filename=\"" + className + " " +  title + ".xlsx\"");
    try (ServletOutputStream output = response.getOutputStream()){
        workbook.write(output);
        output.flush();
    } catch (Exception e) {
        throw new RuntimeException(e);
    }

My Ajax to download file and open download window:

$.ajax({
    url: myUrl,
    type: 'POST',
    data: myData,
    success: function(data, status, xhr) {
        var contentType = 'application/vnd.ms-excel';

        var filename = "";
        var disposition = xhr.getResponseHeader('Content-Disposition');
        if (disposition && disposition.indexOf('attachment') !== -1) {
            var filenameRegex = /filename[^;=\n]*=((['"]).*?\2|[^;\n]*)/;
            var matches = filenameRegex.exec(disposition);
            if (matches != null && matches[1]) filename = matches[1].replace(/['"]/g, '');
        }
        console.log("FILENAME: " + filename);

        try {
            var blob = new Blob([data], { type: contentType });

            var downloadUrl = URL.createObjectURL(blob);
            var a = document.createElement("a");
            a.href = downloadUrl;
            a.download = filename;
            document.body.appendChild(a);
            a.click();

        } catch (exc) {
            console.log("Save Blob method failed with the following exception.");
            console.log(exc);
        }

Answer 1

It looks like JQuery have got some problem with dealing with the binary data from the response. I used simply XMLHttpRequest and I add all data to the URL.

var request = new XMLHttpRequest();
request.open('POST', url, true);
request.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
request.responseType = 'blob';

request.onload = function(e) {
    if (this.status === 200) {
        var blob = this.response;
        if(window.navigator.msSaveOrOpenBlob) {
            window.navigator.msSaveBlob(blob, fileName);
        }
        else{
            var downloadLink = window.document.createElement('a');
            var contentTypeHeader = request.getResponseHeader("Content-Type");
            downloadLink.href = window.URL.createObjectURL(new Blob([blob], { type: contentTypeHeader }));
            downloadLink.download = fileName;
            document.body.appendChild(downloadLink);
            downloadLink.click();
            document.body.removeChild(downloadLink);
           }
       }
   };
   request.send();