docs: function () {
                  stateMemory.discarded = [];
                  if (this._isIE7OrLess) {
                      stateMemory.states = [stateMemory.states[this._currentPos]];
                      return;
                  }
                  var states = stateMemory.states;
                  var expirationTime = ((new Date()).getTime() - this.EXPIRATION_TIME * 1000) + "";
                  for (var i = 0; i < states.length; i++) {
                      if (states[i].id > expirationTime) {
                          break;
                      }
                  }
                  states.splice(0, i);
              }