Routine for getting xml file, transforming it by xsl file and putting the result to select

getXML_BuildByXSLT_putToPage.js

function loadXMLDoc(filename)
{
    if (window.ActiveXObject)
    {
        xhttp = new ActiveXObject("Msxml2.XMLHTTP");
    }
    else
    {
        xhttp = new XMLHttpRequest();
    }
    xhttp.open("GET", filename, false);
    try {xhttp.responseType = "msxml-document"} catch(err) {} // Helping IE11
    xhttp.send("");
    return xhttp.responseXML;
}

function buildXML(xmlPath, xslPath)
{
    const xml = loadXMLDoc(xmlPath);
    const xsl = loadXMLDoc(xslPath);
    // code for IE
    if (window.ActiveXObject || xhttp.responseType == "msxml-document")
    {
        ex = xml.transformNode(xsl);
        return ex;
    }
    // code for Chrome, Firefox, Opera, etc.
    else if (document.implementation && document.implementation.createDocument)
    {
        xsltProcessor = new XSLTProcessor();
        xsltProcessor.importStylesheet(xsl);
        resultDocument = xsltProcessor.transformToFragment(xml, document);
        return resultDocument;
    }
}

$(document).ready(function(){
    $('.selectpicker').selectpicker({
        style: 'btn-info'
        // size: 4
    });

    const list = buildXML('/xslt/list.xml', '/xslt/discipline_selector_options.xsl');
    console.log(list);
    $('.selectpicker').html(list);
    $('.selectpicker').selectpicker('refresh');
});