没有jquery的Ajax parsexml

I have a piece of code to get the unread count of Gmail. It is using jQuery, and I would like to know how to do it without a Javascript library, just with Javascript.

$.ajax({
  type: "GET",
  url: "https://mail.google.com/mail/feed/atom",
  dataType: "xml",
  success: parseXml
});

function parseXml(xml)
{
  var result = $(xml).find("fullcount").text();
  alert("count:" + result);
}

try this

var  xmlhttp=new XMLHttpRequest();

xmlhttp.setRequestHeader("Access-Control-Allow-Origin","https://mail.google.com");
xmlhttp.open("POST","https://mail.google.com/mail/feed/atom",false,"username","pwd");
xmlhttp.send();
xmlDoc=xmlhttp.responseXML;
var mailCount=xmlDoc.getElementsByTagName("entry").length;

ok, Solved

xhrGmail = new XMLHttpRequest();
xhrGmail.open('GET','https://mail.google.com/mail/feed/atom')
xhrGmail.onload = function() { console.log(xhrGmail.responseText.split("<fullcount>")   [1].split("</fullcount>")[0]) }
xhrGmail.send(null);