code: function() {
          if (this.strategies) {
              var strategy, i, len;
              for(i=0, len=this.strategies.length; i<len; i++) {
                  strategy = this.strategies[i];
                  if(strategy.autoDestroy) {
                      strategy.destroy();
                  }
              }
              this.strategies = null;
          }
          if (this.protocol) {
              if(this.protocol.autoDestroy) {
                  this.protocol.destroy();
              }
              this.protocol = null;
          }
          this.destroyFeatures();
          this.features = null;
          this.selectedFeatures = null;
          this.unrenderedFeatures = null;
          if (this.renderer) {
              this.renderer.destroy();
          }
          this.renderer = null;
          this.geometryType = null;
          this.drawn = null;
          OpenLayers.Layer.prototype.destroy.apply(this, arguments);  
      }
docs: APIMethod: destroy
  Destroy this layer