function getXMLRequester()
{
    var xmlhttp_request = false; 
    try 
    { 
        if( window.ActiveXObject )
        { 
            for( var i = 7; i; i--)
            { 
                try
                { 
                    if( i == 2 )
                    { 
                        xmlhttp_request = new ActiveXObject( "Microsoft.XMLHTTP" ); 
                    }
                    else
                    { 
                        xmlhttp_request = new ActiveXObject( "Msxml2.XMLHTTP." + i + ".0" ); 
                        xmlhttp_request.setRequestHeader("Content-Type","text/xml"); 
                        xmlhttp_request.setRequestHeader("Content-Type","gb2312"); 
                    }
                    break;
                 } 
                 catch(e)
                 { 
                    xmlhttp_request = false; 
                 } 
              } 
          }
          else if( window.XMLHttpRequest)
          { 
              xmlhttp_request = new XMLHttpRequest();
              if (xmlhttp_request.overrideMimeType)
              { 
                  xmlhttp_request.overrideMimeType('text/xml'); 
              } 
          } 
      }
      catch(e)
      { 
           xmlhttp_request = false;
      } 
      return xmlhttp_request ; 
}