docs: function (event) {
                  var specialKey = false, keyCode = event.keyCode;
                  for (var index = 0, keyMap; index < this.selectionKeys.length; index++) {
                      keyMap = this.selectionKeys[index];
                      if (this._validateModifiers(keyMap, event)) {
                          // case real key defined. For eg: 65 for a
                          if (ariaUtilsType.isNumber(keyMap.key)) {
                              if (keyMap.key === keyCode) {
                                  specialKey = true;
                                  break;
                              }
                          } else if (typeof(keyMap.key) !== "undefined"
                                  && event["KC_" + keyMap.key.toUpperCase()] == keyCode) {
                              specialKey = true;
                              break;
                          } else if (typeof(keyMap.key) !== "undefined"
                                  && String.fromCharCode(event.charCode) == keyMap.key) {
                              specialKey = true;
                              break;
                          }
                      }
                  }
                  return specialKey;
              }