Parse XML from RSS feed in vanilla JavaScript

parseXML.js

// from: // https://stackoverflow.com/a/17604251/2148418
var parseXml;
if (typeof window.DOMParser != "undefined") {

  parseXml = function(xmlStr) {
    return ( new window.DOMParser() ).parseFromString(xmlStr, "text/xml");
  };

} else if (typeof window.ActiveXObject != "undefined" && new window.ActiveXObject("Microsoft.XMLDOM")) {

  parseXml = function(xmlStr) {
    var xmlDoc = new window.ActiveXObject("Microsoft.XMLDOM");
    xmlDoc.async = "false";
    xmlDoc.loadXML(xmlStr);

    return xmlDoc;
  };

} else {

  throw new Error("No XML parser found");

}

// use: 

var xml = parseXml(response);
var self = xml.querySelectorAll('channel item')[0]; // first post from feed