          function arrowKeyHandler(keyCode) {
            // left, right, up, down key
            var $nextNode;
            var lastRowColumnLength = $specialCharNode.length % totalColumn;

            if (KEY.LEFT === keyCode) {
              if (currentColumn > 1) {
                currentColumn = currentColumn - 1;
              } else if (currentRow === 1 && currentColumn === 1) {
                currentColumn = lastRowColumnLength;
                currentRow = totalRow;
              } else {
                currentColumn = totalColumn;
                currentRow = currentRow - 1;
              }
            } else if (KEY.RIGHT === keyCode) {
              if (currentRow === totalRow && lastRowColumnLength === currentColumn) {
                currentColumn = 1;
                currentRow = 1;
              } else if (currentColumn < totalColumn) {
                currentColumn = currentColumn + 1;
              } else {
                currentColumn = 1;
                currentRow = currentRow + 1;
              }
            } else if (KEY.UP === keyCode) {
              if (currentRow === 1 && lastRowColumnLength < currentColumn) {
                currentRow = totalRow - 1;
              } else {
                currentRow = currentRow - 1;
              }
            } else if (KEY.DOWN === keyCode) {
              currentRow = currentRow + 1;
            }

            if (currentRow === totalRow && currentColumn > lastRowColumnLength) {
              currentRow = 1;
            } else if (currentRow > totalRow) {
              currentRow = 1;
            } else if (currentRow < 1) {
              currentRow = totalRow;
            }

            $nextNode = findNextNode(currentRow, currentColumn);

            if ($nextNode) {
              removeActiveClass($selectedNode);
              addActiveClass($nextNode);
            }
          }
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.