// ajax.js source
var contentType = "application/x-www-form-urlencoded; charset=UTF-8";

// Provide the XMLHttpRequest class for IE 5.x-6.x:
if( typeof XMLHttpRequest == "undefined" ) XMLHttpRequest = function() {
  try { return new ActiveXObject("Msxml2.XMLHTTP.6.0") } catch(e) {}
  try { return new ActiveXObject("Msxml2.XMLHTTP.3.0") } catch(e) {}
  try { return new ActiveXObject("Msxml2.XMLHTTP") } catch(e) {}
  try { return new ActiveXObject("Microsoft.XMLHTTP") } catch(e) {}
  throw new Error( "This browser does not support XMLHttpRequest." )
};

function ajax(url, vars, callbackFunction) {
  var request =  new XMLHttpRequest();
  request.open("POST", url, true);
  request.setRequestHeader("Content-Type", contentType);
 
  request.onreadystatechange = function() {
    if (request.readyState == 4 && request.status == 200) {
      if (request.responseText) {
        callbackFunction(request.responseText);
      }
    };
  }
  request.send(vars);
}