asp.net ajax post + download file

downloadFileAjax.cs

public ActionResult GenerateXLS(string headersJSON, string rowsJSON)
        {
            JavaScriptSerializer srl = new JavaScriptSerializer();
            var headers = srl.Deserialize<List<object>>(headersJSON);
            var rows = srl.Deserialize<List<object[]>>(rowsJSON);
            
            var sheet = _excelCreator.AddSheet("Test");
            _excelCreator.CreateHeaders(sheet, headers);
            _excelCreator.SetColumnsWidth(sheet);

            foreach (var row in rows)
            {
                _excelCreator.AddRow(sheet, row);
            }
            
            var output = _excelCreator.CreateXLS()?.ToArray();
            
            var fileName = "TestXLS_" + DateTime.UtcNow.ToString("yyy-MM-dd") + ".xls";
            var response = System.Web.HttpContext.Current.Response;
            response.ContentType = "application/vnd.ms-excel";
            response.AddHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
            if (output.Length > 0)
            {
                response.OutputStream.Write(output, 0, output.Length);
            }
            response.Flush();
            response.SuppressContent = true;
            return null; 
        }

downloadFileAjax.js

    function XLS() {
        var action = "GenerateXLS";
        var method = "POST";

        var headers = [];
        var rows = [];
        
        $("th").each(function() {
            headers.push(this.innerText);             
        });
        
        $("tr").each(function() {
            var data = [];
            $(this).children("td").each(function() {
                data.push(this.innerText);
            });
            
            if (data.length > 0) {
                rows.push(data);
            }
        });

        downloadFile(action, method, { "headersJSON": JSON.stringify(headers), "rowsJSON": JSON.stringify(rows) });
    }
    
    function downloadFile(action, method, input) {
        "use strict";
        var form;
        form = $('<form />', {
            action: action,
            method: method,
            style: 'display: none;'
        });
        if (typeof input !== 'undefined') {
            $.each(input, function (name, value) {
                $('<input />', {
                    type: 'hidden',
                    name: name,
                    value: value
                }).appendTo(form);
            });
        }
        form.appendTo('body').submit();
    }