code: function(options) {
          this.request = new OpenLayers.Format.ArcXML.Request();
          this.response = new OpenLayers.Format.ArcXML.Response();
  
          if (options) {
              if (options.requesttype == "feature") {
                  this.request.get_image = null;
              
                  var qry = this.request.get_feature.query;
                  this.addCoordSys(qry.featurecoordsys, options.featureCoordSys);
                  this.addCoordSys(qry.filtercoordsys, options.filterCoordSys);
              
                  if (options.polygon) {
                      qry.isspatial = true;
                      qry.spatialfilter.polygon = options.polygon;
                  } else if (options.envelope) {
                      qry.isspatial = true;
                      qry.spatialfilter.envelope = {minx:0, miny:0, maxx:0, maxy:0};
                      this.parseEnvelope(qry.spatialfilter.envelope, options.envelope);
                  }
              } else if (options.requesttype == "image") {
                  this.request.get_feature = null;
              
                  var props = this.request.get_image.properties;
                  this.parseEnvelope(props.envelope, options.envelope);
              
                  this.addLayers(props.layerlist, options.layers);
                  this.addImageSize(props.imagesize, options.tileSize);
                  this.addCoordSys(props.featurecoordsys, options.featureCoordSys);
                  this.addCoordSys(props.filtercoordsys, options.filterCoordSys);
              } else {
                  // if an arcxml object is being created with no request type, it is
                  // probably going to consume a response, so do not throw an error if
                  // the requesttype is not defined
                  this.request = null;
              }
          }
          
          OpenLayers.Format.XML.prototype.initialize.apply(this, [options]);
      }
docs: Constructor: OpenLayers.Format.ArcXML
  Create a new parser/writer for ArcXML.  Create an instance of this class
  to begin authoring a request to an ArcIMS service.  This is used
  primarily by the ArcIMS layer, but could be used to do other wild
  stuff, like geocoding.
  
  Parameters:
  options - {Object} An optional object whose properties will be set on
  this instance.