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