function createXmlHttpRequestObject(){  
  var xmlHttp;  
  try{    
    xmlHttp = new XMLHttpRequest();
  }catch(e){    
    var XmlHttpVersions = new Array("MSXML2.XMLHTTP.6.0",
                                    "MSXML2.XMLHTTP.5.0",
                                    "MSXML2.XMLHTTP.4.0",
                                    "MSXML2.XMLHTTP.3.0",
                                    "MSXML2.XMLHTTP",
                                    "Microsoft.XMLHTTP");
   
    for (var i=0; i<XmlHttpVersions.length && !xmlHttp; i++){
      try{         
        xmlHttp = new ActiveXObject(XmlHttpVersions[i]);
      }catch (e) {}
    }
  }  
  if (!xmlHttp){
    alert("Error creating the XMLHttpRequest object.")
  }else{
    return xmlHttp;
  } 
}