docs: function(url) {
          var matches = OpenLayers.Util.isEquivalentUrl(this.url, url);
          if(!matches && this.layerUrls) {
              for(var i=0, len=this.layerUrls.length; i<len; ++i) {
                  if(OpenLayers.Util.isEquivalentUrl(this.layerUrls[i], url)) {
                      matches = true;
                      break;
                  }
              }
          }
          return matches;
      }