code: function(options) {
          options = options || {};
          this.params = {};
          this.pendingRequests = {};
          OpenLayers.Protocol.prototype.initialize.apply(this, arguments);
          if (!this.format) {
              this.format = new OpenLayers.Format.GeoJSON();
          }
  
          if (!this.filterToParams && OpenLayers.Format.QueryStringFilter) {
              var format = new OpenLayers.Format.QueryStringFilter({
                  srsInBBOX: this.srsInBBOX
              });
              this.filterToParams = function(filter, params) {
                  return format.write(filter, params);
              };
          }
      }
docs: Constructor: OpenLayers.Protocol.Script
  A class for giving layers generic Script protocol.
  
  Parameters:
  options - {Object} Optional object whose properties will be set on the
  instance.
  
  Valid options include:
  url - {String}
  params - {Object}
  callback - {Function}
  scope - {Object}