// parts of this script were copied & pasted from www.w3schools.com
// http://www.w3schools.com/ajax/ajax_xmlfile.asp
// thank you very much, w3schools, you've helped me a lot =)

var xmlHttp

function AJAXrequest(request, returnfunction) {
  xmlHttp=GetXmlHttpObject();
  if (xmlHttp==null) {
    return false;
  }
  if (request.indexOf('?') > -1) {
    request = request + '&random=' + Math.random()
  } else {
    request = request + '?random=' + Math.random()
  }
  xmlHttp.onreadystatechange = returnfunction;
  xmlHttp.open("GET", request, true);
  xmlHttp.send(null);
  return true;
}

function AJAXpost(request, data, returnfunction) {
  xmlHttp=GetXmlHttpObject();
  if (xmlHttp==null) {
    return false;
  }
  xmlHttp.onreadystatechange = returnfunction;
  xmlHttp.open("POST", request, true);
  xmlHttp.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
  xmlHttp.setRequestHeader('Content-Length', data.length);
  xmlHttp.send(data);
  return true;
}

function GetXmlHttpObject() {
  var xmlHttp = null;
  try {
    xmlHttp = new XMLHttpRequest();
  } catch (e) {
    try {
      xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
    } catch (e) {
      xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
  }
  return xmlHttp;
}