function createXMLHttpRequest(cbFunc)
{
  var XMLhttpObject = null;
  try{
    XMLhttpObject = new XMLHttpRequest();
  }catch(e){
    try{
      XMLhttpObject = new ActiveXObject("Msxml2.XMLHTTP");
    }catch(e){
      try{
        XMLhttpObject = new ActiveXObject("Microsoft.XMLHTTP");
      }catch(e){
        return null;
      }
    }
  }
  if ((XMLhttpObject) && (cbFunc != "")) XMLhttpObject.onreadystatechange = cbFunc;
  return XMLhttpObject;
}

// This code is taken from "AJAXを勉強しよう"
// http://www.openspc2.org/JavaScript/Ajax/Ajax_study/index.html