var http = (window.XMLHttpRequest) ? new XMLHttpRequest() : new ActiveXObject("Microsoft.XMLHTTP");

function ratingResponseHandler() {
  if (http.readyState == 4) {
    var rating  = document.getElementById('rating');
    var current = document.getElementById('currentrating');
    if(http.status == 200) {
      current.innerHTML = http.responseXML.getElementsByTagName('text')[0].firstChild.nodeValue;
      rating.className = http.responseXML.getElementByTagName('stars')[0].firstChild.nodeValue;
    } else {
      current.innerHTML = 'Error!';
    }
  }
}

function submitRating(url) {
  var obj = document.getElementById('currentrating');
  obj.innerHTML = 'Submitting rating...';
  http.open('get', url + '&ajax=1');
  http.onreadystatechange = ratingResponseHandler;
  http.send(null);
  return false;
}