} else if (isPageDown(keyCode)) {
chart.pageRight(FULL_PAGE_SCROLL);
} else if (event.isRightArrow() || isKeyRight(keyCode)) {
chart.pageRight(HALF_PAGE_SCROLL);
} else if (event.isUpArrow() || isNextZoom(keyCode)) {
chart.nextZoom();
ChartKeyDownHandler.UP_NUM = 0;
} else if (event.isDownArrow() || isPrevZoom(keyCode)) {
chart.prevZoom();
ChartKeyDownHandler.DOWN_NUM = 0;
} else if (keyCode == KeyCodes.KEY_BACKSPACE) {