/**
 * @license Highcharts JS v5.0.6 (2016-12-07)
 * Accessibility module
 *
 * (c) 2010-2016 Highsoft AS
 * Author: Oystein Moseng
 *
 * License: www.highcharts.com/license
 */
(function(factory) {
    if (typeof module === 'object' && module.exports) {
        module.exports = factory;
    } else {
        factory(Highcharts);
    }
}(function(Highcharts) {
    (function(H) {
        /**
         * Accessibility module
         *
         * (c) 2010-2016 Highsoft AS
         * Author: Oystein Moseng
         *
         * License: www.highcharts.com/license
         */
        'use strict';

        var win = H.win,
            doc = win.document,
            each = H.each,
            erase = H.erase,
            addEvent = H.addEvent,
            removeEvent = H.removeEvent,
            fireEvent = H.fireEvent,
            dateFormat = H.dateFormat,
            merge = H.merge,
            // Human readable description of series and each point in singular and plural
            typeToSeriesMap = {
                'default': ['series', 'data point', 'data points'],
                'line': ['line', 'data point', 'data points'],
                'spline': ['line', 'data point', 'data points'],
                'area': ['line', 'data point', 'data points'],
                'areaspline': ['line', 'data point', 'data points'],
                'pie': ['pie', 'slice', 'slices'],
                'column': ['column series', 'column', 'columns'],
                'bar': ['bar series', 'bar', 'bars'],
                'scatter': ['scatter series', 'data point', 'data points'],
                'boxplot': ['boxplot series', 'box', 'boxes'],
                'arearange': ['arearange series', 'data point', 'data points'],
                'areasplinerange': ['areasplinerange series', 'data point', 'data points'],
                'bubble': ['bubble series', 'bubble', 'bubbles'],
                'columnrange': ['columnrange series', 'column', 'columns'],
                'errorbar': ['errorbar series', 'errorbar', 'errorbars'],
                'funnel': ['funnel', 'data point', 'data points'],
                'pyramid': ['pyramid', 'data point', 'data points'],
                'waterfall': ['waterfall series', 'column', 'columns'],
                'map': ['map', 'area', 'areas'],
                'mapline': ['line', 'data point', 'data points'],
                'mappoint': ['point series', 'data point', 'data points'],
                'mapbubble': ['bubble series', 'bubble', 'bubbles']
            },
            // Descriptions for exotic chart types
            typeDescriptionMap = {
                boxplot: ' Box plot charts are typically used to display groups of statistical data. ' +
                    'Each data point in the chart can have up to 5 values: minimum, lower quartile, median, upper quartile and maximum. ',
                arearange: ' Arearange charts are line charts displaying a range between a lower and higher value for each point. ',
                areasplinerange: ' These charts are line charts displaying a range between a lower and higher value for each point. ',
                bubble: ' Bubble charts are scatter charts where each data point also has a size value. ',
                columnrange: ' Columnrange charts are column charts displaying a range between a lower and higher value for each point. ',
                errorbar: ' Errorbar series are used to display the variability of the data. ',
                funnel: ' Funnel charts are used to display reduction of data in stages. ',
                pyramid: ' Pyramid charts consist of a single pyramid with item heights corresponding to each point value. ',
                waterfall: ' A waterfall chart is a column chart where each column contributes towards a total end value. '
            },
            commonKeys = ['name', 'id', 'category', 'x', 'value', 'y'],
            specialKeys = ['z', 'open', 'high', 'q3', 'median', 'q1', 'low', 'close']; // Tell user about all properties if points have one of these defined

        // Default a11y options
        H.setOptions({
            accessibility: {
                enabled: true,
                pointDescriptionThreshold: 30, // set to false to disable
                keyboardNavigation: {
                    enabled: true
                        //	skipNullPoints: false
                }
                // describeSingleSeries: false
            }
        });

        // Utility function. Reverses child nodes of a DOM element
        function reverseChildNodes(node) {
            var i = node.childNodes.length;
            while (i--) {
                node.appendChild(node.childNodes[i]);
            }
        }

        // Utility function to attempt to fake a click event on an element
        function fakeClickEvent(element) {
            var fakeEvent;
            if (element && element.onclick) {
                fakeEvent = doc.createEvent('Events');
                fakeEvent.initEvent('click', true, false);
                element.onclick(fakeEvent);
            }
        }

        // Whenever drawing series, put info on DOM elements
        H.wrap(H.Series.prototype, 'render', function(proceed) {
            proceed.apply(this, Array.prototype.slice.call(arguments, 1));
            if (this.chart.options.accessibility.enabled) {
                this.setA11yDescription();
            }
        });

        // Put accessible info on series and points of a series
        H.Series.prototype.setA11yDescription = function() {
            var a11yOptions = this.chart.options.accessibility,
                firstPointEl = this.points && this.points.length && this.points[0].graphic && this.points[0].graphic.element,
                seriesEl = firstPointEl && firstPointEl.parentNode || this.graph && this.graph.element || this.group && this.group.element; // Could be tracker series depending on series type

            if (seriesEl) {
                // For some series types the order of elements do not match the order of points in series
                // In that case we have to reverse them in order for AT to read them out in an understandable order
                if (seriesEl.lastChild === firstPointEl) {
                    reverseChildNodes(seriesEl);
                }
                // Make individual point elements accessible if possible. Note: If markers are disabled there might not be any elements there to make accessible.
                if (this.points && (this.points.length < a11yOptions.pointDescriptionThreshold || a11yOptions.pointDescriptionThreshold === false)) {
                    each(this.points, function(point) {
                        if (point.graphic) {
                            point.graphic.element.setAttribute('role', 'img');
                            point.graphic.element.setAttribute('tabindex', '-1');
                            point.graphic.element.setAttribute('aria-label', a11yOptions.pointDescriptionFormatter && a11yOptions.pointDescriptionFormatter(point) ||
                                point.buildPointInfoString());
                        }
                    });
                }
                // Make series element accessible
                if (this.chart.series.length > 1 || a11yOptions.describeSingleSeries) {
                    seriesEl.setAttribute('role', 'region');
                    seriesEl.setAttribute('tabindex', '-1');
                    seriesEl.setAttribute('aria-label', a11yOptions.seriesDescriptionFormatter && a11yOptions.seriesDescriptionFormatter(this) ||
                        this.buildSeriesInfoString());
                }
            }
        };

        // Return string with information about series
        H.Series.prototype.buildSeriesInfoString = function() {
            var typeInfo = typeToSeriesMap[this.type] || typeToSeriesMap.default,
                description = this.description || this.options.description;
            return (this.name ? this.name + ', ' : '') +
                (this.chart.types.length === 1 ? typeInfo[0] : 'series') + ' ' + (this.index + 1) + ' of ' + (this.chart.series.length) +
                (this.chart.types.length === 1 ? ' with ' : '. ' + typeInfo[0] + ' with ') +
                (this.points.length + ' ' + (this.points.length === 1 ? typeInfo[1] : typeInfo[2])) +
                (description ? '. ' + description : '') +
                (this.chart.yAxis.length > 1 && this.yAxis ? '. Y axis, ' + this.yAxis.getDescription() : '') +
                (this.chart.xAxis.length > 1 && this.xAxis ? '. X axis, ' + this.xAxis.getDescription() : '');
        };

        // Return string with information about point
        H.Point.prototype.buildPointInfoString = function() {
            var point = this,
                series = point.series,
                a11yOptions = series.chart.options.accessibility,
                infoString = '',
                hasSpecialKey = false,
                dateTimePoint = series.xAxis && series.xAxis.isDatetimeAxis,
                timeDesc = dateTimePoint && dateFormat(a11yOptions.pointDateFormatter && a11yOptions.pointDateFormatter(point) || a11yOptions.pointDateFormat ||
                    H.Tooltip.prototype.getXDateFormat(point, series.chart.options.tooltip, series.xAxis), point.x);

            each(specialKeys, function(key) {
                if (point[key] !== undefined) {
                    hasSpecialKey = true;
                }
            });

            // If the point has one of the less common properties defined, display all that are defined
            if (hasSpecialKey) {
                if (dateTimePoint) {
                    infoString = timeDesc;
                }
                each(commonKeys.concat(specialKeys), function(key) {
                    if (point[key] !== undefined && !(dateTimePoint && key === 'x')) {
                        infoString += (infoString ? '. ' : '') + key + ', ' + this[key];
                    }
                });
            } else {
                // Pick and choose properties for a succint label
                infoString = (this.name || timeDesc || this.category || this.id || 'x, ' + this.x) + ', ' +
                    (this.value !== undefined ? this.value : this.y);
            }

            return (this.index + 1) + '. ' + infoString + '.' + (this.description ? ' ' + this.description : '');
        };

        // Get descriptive label for axis
        H.Axis.prototype.getDescription = function() {
            return this.userOptions && this.userOptions.description || this.axisTitle && this.axisTitle.textStr ||
                this.options.id || this.categories && 'categories' || 'values';
        };

        // Pan along axis in a direction (1 or -1), optionally with a defined granularity (number of steps it takes to walk across current view)
        H.Axis.prototype.panStep = function(direction, granularity) {
            var gran = granularity || 3,
                extremes = this.getExtremes(),
                step = (extremes.max - extremes.min) / gran * direction,
                newMax = extremes.max + step,
                newMin = extremes.min + step,
                size = newMax - newMin;
            if (direction < 0 && newMin < extremes.dataMin) {
                newMin = extremes.dataMin;
                newMax = newMin + size;
            } else if (direction > 0 && newMax > extremes.dataMax) {
                newMax = extremes.dataMax;
                newMin = newMax - size;
            }
            this.setExtremes(newMin, newMax);
        };

        // Whenever adding or removing series, keep track of types present in chart
        H.wrap(H.Series.prototype, 'init', function(proceed) {
            proceed.apply(this, Array.prototype.slice.call(arguments, 1));
            var chart = this.chart;
            if (chart.options.accessibility.enabled) {
                chart.types = chart.types || [];

                // Add type to list if does not exist
                if (chart.types.indexOf(this.type) < 0) {
                    chart.types.push(this.type);
                }

                addEvent(this, 'remove', function() {
                    var removedSeries = this,
                        hasType = false;

                    // Check if any of the other series have the same type as this one. Otherwise remove it from the list.
                    each(chart.series, function(s) {
                        if (s !== removedSeries && chart.types.indexOf(removedSeries.type) < 0) {
                            hasType = true;
                        }
                    });
                    if (!hasType) {
                        erase(chart.types, removedSeries.type);
                    }
                });
            }
        });

        // Return simplified description of chart type. Some types will not be familiar to most screen reader users, but we try.
        H.Chart.prototype.getTypeDescription = function() {
            var firstType = this.types && this.types[0],
                mapTitle = this.series[0] && this.series[0].mapTitle;
            if (!firstType) {
                return 'Empty chart.';
            } else if (firstType === 'map') {
                return mapTitle ? 'Map of ' + mapTitle : 'Map of unspecified region.';
            } else if (this.types.length > 1) {
                return 'Combination chart.';
            } else if (['spline', 'area', 'areaspline'].indexOf(firstType) > -1) {
                return 'Line chart.';
            }
            return firstType + ' chart.' + (typeDescriptionMap[firstType] || '');
        };

        // Return object with text description of each of the chart's axes
        H.Chart.prototype.getAxesDescription = function() {
            var numXAxes = this.xAxis.length,
                numYAxes = this.yAxis.length,
                desc = {},
                i;

            if (numXAxes) {
                desc.xAxis = 'The chart has ' + numXAxes + (numXAxes > 1 ? ' X axes' : ' X axis') + ' displaying ';
                if (numXAxes < 2) {
                    desc.xAxis += this.xAxis[0].getDescription() + '.';
                } else {
                    for (i = 0; i < numXAxes - 1; ++i) {
                        desc.xAxis += (i ? ', ' : '') + this.xAxis[i].getDescription();
                    }
                    desc.xAxis += ' and ' + this.xAxis[i].getDescription() + '.';
                }
            }

            if (numYAxes) {
                desc.yAxis = 'The chart has ' + numYAxes + (numYAxes > 1 ? ' Y axes' : ' Y axis') + ' displaying ';
                if (numYAxes < 2) {
                    desc.yAxis += this.yAxis[0].getDescription() + '.';
                } else {
                    for (i = 0; i < numYAxes - 1; ++i) {
                        desc.yAxis += (i ? ', ' : '') + this.yAxis[i].getDescription();
                    }
                    desc.yAxis += ' and ' + this.yAxis[i].getDescription() + '.';
                }
            }

            return desc;
        };

        // Set a11y attribs on exporting menu
        H.Chart.prototype.addAccessibleContextMenuAttribs = function() {
            var exportList = this.exportDivElements;
            if (exportList) {
                // Set tabindex on the menu items to allow focusing by script
                // Set role to give screen readers a chance to pick up the contents
                each(exportList, function(item) {
                    if (item.tagName === 'DIV' &&
                        !(item.children && item.children.length)) {
                        item.setAttribute('role', 'menuitem');
                        item.setAttribute('tabindex', -1);
                    }
                });
                // Set accessibility properties on parent div
                exportList[0].parentNode.setAttribute('role', 'menu');
                exportList[0].parentNode.setAttribute('aria-label', 'Chart export');
            }
        };

        // Highlight a point (show tooltip and display hover state). Returns the highlighted point.
        H.Point.prototype.highlight = function() {
            var chart = this.series.chart;
            if (this.graphic && this.graphic.element.focus) {
                this.graphic.element.focus();
            }
            if (!this.isNull) {
                this.onMouseOver(); // Show the hover marker
                chart.tooltip.refresh(chart.tooltip.shared ? [this] : this); // Show the tooltip
            } else {
                chart.tooltip.hide(0);
                // Don't call blur on the element, as it messes up the chart div's focus
            }
            chart.highlightedPoint = this;
            return this;
        };

        // Function to highlight next/previous point in chart
        // Returns highlighted point on success, false on failure (no adjacent point to highlight in chosen direction)
        H.Chart.prototype.highlightAdjacentPoint = function(next) {
            var series = this.series,
                curPoint = this.highlightedPoint,
                curPointIndex = curPoint && curPoint.index || 0,
                newSeries,
                newPoint;

            // If no points, return false
            if (!series[0] || !series[0].points) {
                return false;
            }

            // Use first point if none already highlighted
            if (!curPoint) {
                return series[0].points[0].highlight();
            }

            // Find index of current point in series.points array. Necessary for dataGrouping (and maybe zoom?)
            if (curPoint.series.points[curPointIndex] !== curPoint) {
                for (var i = 0; i < curPoint.series.points.length; ++i) {
                    if (curPoint.series.points[i] === curPoint) {
                        curPointIndex = i;
                        break;
                    }
                }
            }

            // Try to grab next/prev point
            newSeries = series[curPoint.series.index + (next ? 1 : -1)];
            newPoint = curPoint.series.points[curPointIndex + (next ? 1 : -1)] || newSeries && newSeries.points[next ? 0 : newSeries.points.length - 1];

            // If there is no adjacent point, we return false
            if (newPoint === undefined) {
                return false;
            }

            // Recursively skip null points
            if (newPoint.isNull && this.options.accessibility.keyboardNavigation &&
                this.options.accessibility.keyboardNavigation.skipNullPoints) {
                this.highlightedPoint = newPoint;
                return this.highlightAdjacentPoint(next);
            }

            // There is an adjacent point, highlight it
            return newPoint.highlight();
        };

        // Show the export menu and focus the first item (if exists)
        H.Chart.prototype.showExportMenu = function() {
            if (this.exportSVGElements && this.exportSVGElements[0]) {
                this.exportSVGElements[0].element.onclick();
                this.highlightExportItem(0);
            }
        };

        // Highlight export menu item by index
        H.Chart.prototype.highlightExportItem = function(ix) {
            var listItem = this.exportDivElements && this.exportDivElements[ix],
                curHighlighted = this.exportDivElements && this.exportDivElements[this.highlightedExportItem];

            if (listItem && listItem.tagName === 'DIV' && !(listItem.children && listItem.children.length)) {
                if (listItem.focus) {
                    listItem.focus();
                }
                if (curHighlighted && curHighlighted.onmouseout) {
                    curHighlighted.onmouseout();
                }
                if (listItem.onmouseover) {
                    listItem.onmouseover();
                }
                this.highlightedExportItem = ix;
                return true;
            }
        };

        // Highlight range selector button by index
        H.Chart.prototype.highlightRangeSelectorButton = function(ix) {
            var buttons = this.rangeSelector.buttons;
            // Deselect old
            if (buttons[this.highlightedRangeSelectorItemIx]) {
                buttons[this.highlightedRangeSelectorItemIx].setState(this.oldRangeSelectorItemState || 0);
            }
            // Select new
            this.highlightedRangeSelectorItemIx = ix;
            if (buttons[ix]) {
                if (buttons[ix].element.focus) {
                    buttons[ix].element.focus();
                }
                this.oldRangeSelectorItemState = buttons[ix].state;
                buttons[ix].setState(2);
                return true;
            }
            return false;
        };

        // Highlight legend item by index
        H.Chart.prototype.highlightLegendItem = function(ix) {
            var items = this.legend.allItems;
            if (items[this.highlightedLegendItemIx]) {
                fireEvent(items[this.highlightedLegendItemIx].legendGroup.element, 'mouseout');
            }
            this.highlightedLegendItemIx = ix;
            if (items[ix]) {
                if (items[ix].legendGroup.element.focus) {
                    items[ix].legendGroup.element.focus();
                }
                fireEvent(items[ix].legendGroup.element, 'mouseover');
                return true;
            }
            return false;
        };

        // Hide export menu
        H.Chart.prototype.hideExportMenu = function() {
            var exportList = this.exportDivElements;
            if (exportList) {
                each(exportList, function(el) {
                    fireEvent(el, 'mouseleave');
                });
                if (exportList[this.highlightedExportItem] && exportList[this.highlightedExportItem].onmouseout) {
                    exportList[this.highlightedExportItem].onmouseout();
                }
                this.highlightedExportItem = 0;
                this.renderTo.focus();
            }
        };

        // Add keyboard navigation handling to chart
        H.Chart.prototype.addKeyboardNavEvents = function() {
            var chart = this;

            // Abstraction layer for keyboard navigation. Keep a map of keyCodes to handler functions, and a next/prev move handler for tab order.
            // The module's keyCode handlers determine when to move to another module.
            // Validate holds a function to determine if there are prerequisites for this module to run that are not met.
            // Init holds a function to run once before any keyCodes are interpreted.
            // transformTabs determines whether to transform tabs to left/right events or not. Defaults to true.
            function KeyboardNavigationModule(options) {
                this.keyCodeMap = options.keyCodeMap;
                this.move = options.move;
                this.validate = options.validate;
                this.init = options.init;
                this.transformTabs = options.transformTabs !== false;
            }
            KeyboardNavigationModule.prototype = {
                // Find handler function(s) for key code in the keyCodeMap and run it.
                run: function(e) {
                    var navModule = this,
                        keyCode = e.which || e.keyCode,
                        handled = false;
                    keyCode = this.transformTabs && keyCode === 9 ? (e.shiftKey ? 37 : 39) : keyCode; // Transform tabs
                    each(this.keyCodeMap, function(codeSet) {
                        if (codeSet[0].indexOf(keyCode) > -1) {
                            handled = codeSet[1].call(navModule, keyCode, e) === false ? false : true; // If explicitly returning false, we haven't handled it
                        }
                    });
                    return handled;
                }
            };
            // Maintain abstraction between KeyboardNavigationModule and Highcharts
            // The chart object keeps track of a list of KeyboardNavigationModules that we move through
            function navModuleFactory(keyMap, options) {
                return new KeyboardNavigationModule(merge({
                    keyCodeMap: keyMap,
                    // Move to next/prev valid module, or undefined if none, and init it.
                    // Returns true on success and false if there is no valid module to move to.
                    move: function(direction) {
                        chart.keyboardNavigationModuleIndex += direction;
                        var newModule = chart.keyboardNavigationModules[chart.keyboardNavigationModuleIndex];
                        if (newModule) {
                            if (newModule.validate && !newModule.validate()) {
                                return this.move(direction); // Invalid module
                            }
                            if (newModule.init) {
                                newModule.init(direction); // Valid module, init it
                                return true;
                            }
                        }
                        // No module
                        chart.keyboardNavigationModuleIndex = 0; // Reset counter
                        chart.slipNextTab = true; // Allow next tab to slip, as we will have focus on chart now
                        return false;
                    }
                }, options));
            }

            // Route keydown events
            function keydownHandler(ev) {
                var e = ev || win.event,
                    keyCode = e.which || e.keyCode,
                    curNavModule = chart.keyboardNavigationModules[chart.keyboardNavigationModuleIndex];

                // Handle tabbing
                if (keyCode === 9) {
                    // If we reached end of chart, we need to let this tab slip through to allow users to tab further
                    if (chart.slipNextTab) {
                        chart.slipNextTab = false;
                        return;
                    }
                }
                // If key was not tab, don't slip the next tab
                chart.slipNextTab = false;

                // If there is a navigation module for the current index, run it. Otherwise, we are outside of the chart in some direction.
                if (curNavModule) {
                    if (curNavModule.run(e)) {
                        e.preventDefault(); // If successfully handled, stop the event here.
                    }
                }
            }

            // List of the different keyboard handling modes we use depending on where we are in the chart.
            // Each mode has a set of handling functions mapped to key codes.
            // Each mode determines when to move to the next/prev mode.
            chart.keyboardNavigationModules = [
                // Points
                navModuleFactory([
                    // Left/Right
                    [
                        [37, 39],
                        function(keyCode) {
                            if (!chart.highlightAdjacentPoint(keyCode === 39)) { // Try to highlight adjacent point
                                return this.move(keyCode === 39 ? 1 : -1); // Failed. Move to next/prev module
                            }
                        }
                    ],
                    // Up/Down
                    [
                        [38, 40],
                        function(keyCode) {
                            var newSeries;
                            if (chart.highlightedPoint) {
                                newSeries = chart.series[chart.highlightedPoint.series.index + (keyCode === 38 ? -1 : 1)]; // Find prev/next series
                                if (newSeries && newSeries.points[0]) { // If series exists and has data, go for it
                                    newSeries.points[0].highlight();
                                } else {
                                    return this.move(keyCode === 40 ? 1 : -1); // Otherwise, attempt to move to next/prev module
                                }
                            }
                        }
                    ],
                    // Enter/Spacebar
                    [
                        [13, 32],
                        function() {
                            if (chart.highlightedPoint) {
                                chart.highlightedPoint.firePointEvent('click');
                            }
                        }
                    ]
                ], {
                    // If coming back to points from other module, highlight last point
                    init: function(direction) {
                        var lastSeries = chart.series && chart.series[chart.series.length - 1],
                            lastPoint = lastSeries && lastSeries.points && lastSeries.points[lastSeries.points.length - 1];
                        if (direction < 0 && lastPoint) {
                            lastPoint.highlight();
                        }
                    }
                }),

                // Exporting
                navModuleFactory([
                    // Left/Up
                    [
                        [37, 38],
                        function() {
                            var i = chart.highlightedExportItem || 0,
                                reachedEnd = true,
                                series = chart.series,
                                newSeries;
                            // Try to highlight prev item in list. Highlighting e.g. separators will fail.
                            while (i--) {
                                if (chart.highlightExportItem(i)) {
                                    reachedEnd = false;
                                    break;
                                }
                            }
                            if (reachedEnd) {
                                chart.hideExportMenu();
                                // Wrap to last point
                                if (series && series.length) {
                                    newSeries = series[series.length - 1];
                                    if (newSeries.points.length) {
                                        newSeries.points[newSeries.points.length - 1].highlight();
                                    }
                                }
                                // Try to move to prev module (should be points, since we wrapped to last point)
                                return this.move(-1);
                            }
                        }
                    ],
                    // Right/Down
                    [
                        [39, 40],
                        function() {
                            var highlightedExportItem = chart.highlightedExportItem || 0,
                                reachedEnd = true;
                            // Try to highlight next item in list. Highlighting e.g. separators will fail.
                            for (var i = highlightedExportItem + 1; i < chart.exportDivElements.length; ++i) {
                                if (chart.highlightExportItem(i)) {
                                    reachedEnd = false;
                                    break;
                                }
                            }
                            if (reachedEnd) {
                                chart.hideExportMenu();
                                return this.move(1); // Next module
                            }
                        }
                    ],
                    // Enter/Spacebar
                    [
                        [13, 32],
                        function() {
                            fakeClickEvent(chart.exportDivElements[chart.highlightedExportItem]);
                        }
                    ]
                ], {
                    // Only run exporting navigation if exporting support exists and is enabled on chart
                    validate: function() {
                        return chart.exportChart && !(chart.options.exporting && chart.options.exporting.enabled === false);
                    },
                    // Show export menu
                    init: function(direction) {
                        chart.highlightedPoint = null;
                        chart.showExportMenu();
                        // If coming back to export menu from other module, try to highlight last item in menu
                        if (direction < 0 && chart.exportDivElements) {
                            for (var i = chart.exportDivElements.length; i > -1; --i) {
                                if (chart.highlightExportItem(i)) {
                                    break;
                                }
                            }
                        }
                    }
                }),

                // Map zoom
                navModuleFactory([
                    // Up/down/left/right
                    [
                        [38, 40, 37, 39],
                        function(keyCode) {
                            chart[keyCode === 38 || keyCode === 40 ? 'yAxis' : 'xAxis'][0].panStep(keyCode < 39 ? -1 : 1);
                        }
                    ],

                    // Tabs
                    [
                        [9],
                        function(keyCode, e) {
                            var button;
                            chart.mapNavButtons[chart.focusedMapNavButtonIx].setState(0); // Deselect old
                            if (e.shiftKey && !chart.focusedMapNavButtonIx || !e.shiftKey && chart.focusedMapNavButtonIx) { // trying to go somewhere we can't?
                                chart.mapZoom(); // Reset zoom
                                return this.move(e.shiftKey ? -1 : 1); // Nowhere to go, go to prev/next module
                            }
                            chart.focusedMapNavButtonIx += e.shiftKey ? -1 : 1;
                            button = chart.mapNavButtons[chart.focusedMapNavButtonIx];
                            if (button.element.focus) {
                                button.element.focus();
                            }
                            button.setState(2);
                        }
                    ],

                    // Enter/Spacebar
                    [
                        [13, 32],
                        function() {
                            fakeClickEvent(chart.mapNavButtons[chart.focusedMapNavButtonIx].element);
                        }
                    ]
                ], {
                    // Only run this module if we have map zoom on the chart
                    validate: function() {
                        return chart.mapZoom && chart.mapNavButtons && chart.mapNavButtons.length === 2;
                    },

                    // Handle tabs separately
                    transformTabs: false,

                    // Make zoom buttons do their magic
                    init: function(direction) {
                        var zoomIn = chart.mapNavButtons[0],
                            zoomOut = chart.mapNavButtons[1],
                            initialButton = direction > 0 ? zoomIn : zoomOut;

                        each(chart.mapNavButtons, function(button, i) {
                            button.element.setAttribute('tabindex', -1);
                            button.element.setAttribute('role', 'button');
                            button.element.setAttribute('aria-label', 'Zoom ' + (i ? 'out' : '') + 'chart');
                        });

                        if (initialButton.element.focus) {
                            initialButton.element.focus();
                        }
                        initialButton.setState(2);
                        chart.focusedMapNavButtonIx = direction > 0 ? 0 : 1;
                    }
                }),

                // Highstock range selector (minus input boxes)
                navModuleFactory([
                    // Left/Right/Up/Down
                    [
                        [37, 39, 38, 40],
                        function(keyCode) {
                            var direction = (keyCode === 37 || keyCode === 38) ? -1 : 1;
                            // Try to highlight next/prev button
                            if (!chart.highlightRangeSelectorButton(chart.highlightedRangeSelectorItemIx + direction)) {
                                return this.move(direction);
                            }
                        }
                    ],
                    // Enter/Spacebar
                    [
                        [13, 32],
                        function() {
                            if (chart.oldRangeSelectorItemState !== 3) { // Don't allow click if button used to be disabled
                                fakeClickEvent(chart.rangeSelector.buttons[chart.highlightedRangeSelectorItemIx].element);
                            }
                        }
                    ]
                ], {
                    // Only run this module if we have range selector
                    validate: function() {
                        return chart.rangeSelector && chart.rangeSelector.buttons && chart.rangeSelector.buttons.length;
                    },

                    // Make elements focusable and accessible
                    init: function(direction) {
                        each(chart.rangeSelector.buttons, function(button) {
                            button.element.setAttribute('tabindex', '-1');
                            button.element.setAttribute('role', 'button');
                            button.element.setAttribute('aria-label', 'Select range ' + (button.text && button.text.textStr));
                        });
                        // Focus first/last button
                        chart.highlightRangeSelectorButton(direction > 0 ? 0 : chart.rangeSelector.buttons.length - 1);
                    }
                }),

                // Highstock range selector, input boxes
                navModuleFactory([
                    // Tab/Up/Down
                    [
                        [9, 38, 40],
                        function(keyCode, e) {
                            var direction = (keyCode === 9 && e.shiftKey || keyCode === 38) ? -1 : 1,
                                newIx = chart.highlightedInputRangeIx = chart.highlightedInputRangeIx + direction;
                            // Try to highlight next/prev item in list.
                            if (newIx > 1 || newIx < 0) { // Out of range
                                return this.move(direction);
                            }
                            chart.rangeSelector[newIx ? 'maxInput' : 'minInput'].focus(); // Input boxes are HTML, and should have focus support in all browsers
                        }
                    ]
                ], {
                    // Only run if we have range selector with input boxes
                    validate: function() {
                        var inputVisible = chart.rangeSelector && chart.rangeSelector.inputGroup && chart.rangeSelector.inputGroup.element.getAttribute('visibility') !== 'hidden';
                        return inputVisible && chart.options.rangeSelector.inputEnabled !== false && chart.rangeSelector.minInput && chart.rangeSelector.maxInput;
                    },

                    // Handle tabs different from left/right (because we don't want to catch left/right in a text area)
                    transformTabs: false,

                    // Highlight first/last input box
                    init: function(direction) {
                        chart.highlightedInputRangeIx = direction > 0 ? 0 : 1;
                        chart.rangeSelector[chart.highlightedInputRangeIx ? 'maxInput' : 'minInput'].focus();
                    }
                }),

                // Legend navigation
                navModuleFactory([
                    // Left/Right/Up/Down
                    [
                        [37, 39, 38, 40],
                        function(keyCode) {
                            var direction = (keyCode === 37 || keyCode === 38) ? -1 : 1;
                            // Try to highlight next/prev legend item
                            if (!chart.highlightLegendItem(chart.highlightedLegendItemIx + direction)) {
                                return this.move(direction);
                            }
                        }
                    ],
                    // Enter/Spacebar
                    [
                        [13, 32],
                        function() {
                            fakeClickEvent(chart.legend.allItems[chart.highlightedLegendItemIx].legendItem.element.parentNode);
                        }
                    ]
                ], {
                    // Only run this module if we have at least one legend - wait for it - item.
                    validate: function() {
                        return chart.legend && chart.legend.allItems && !chart.colorAxis;
                    },

                    // Make elements focusable and accessible
                    init: function(direction) {
                        each(chart.legend.allItems, function(item) {
                            item.legendGroup.element.setAttribute('tabindex', '-1');
                            item.legendGroup.element.setAttribute('role', 'button');
                            item.legendGroup.element.setAttribute('aria-label', 'Toggle visibility of series ' + item.name);
                        });
                        // Focus first/last item
                        chart.highlightLegendItem(direction > 0 ? 0 : chart.legend.allItems.length - 1);
                    }
                })
            ];

            // Init nav module index. We start at the first module, and as the user navigates through the chart the index will increase to use different handler modules.
            chart.keyboardNavigationModuleIndex = 0;

            // Make chart reachable by tab
            if (!chart.renderTo.tabIndex) {
                chart.renderTo.setAttribute('tabindex', '0');
            }

            // Handle keyboard events
            addEvent(chart.renderTo, 'keydown', keydownHandler);
            addEvent(chart, 'destroy', function() {
                removeEvent(chart.renderTo, 'keydown', keydownHandler);
            });
        };

        // Add screen reader region to chart.
        // tableId is the HTML id of the table to focus when clicking the table anchor in the screen reader region.
        H.Chart.prototype.addScreenReaderRegion = function(tableId) {
            var chart = this,
                series = chart.series,
                options = chart.options,
                a11yOptions = options.accessibility,
                hiddenSection = chart.screenReaderRegion = doc.createElement('div'),
                tableShortcut = doc.createElement('h3'),
                tableShortcutAnchor = doc.createElement('a'),
                chartHeading = doc.createElement('h3'),
                hiddenStyle = { // CSS style to hide element from visual users while still exposing it to screen readers
                    position: 'absolute',
                    left: '-9999px',
                    top: 'auto',
                    width: '1px',
                    height: '1px',
                    overflow: 'hidden'
                },
                chartTypes = chart.types || [],
                // Build axis info - but not for pies and maps. Consider not adding for certain other types as well (funnel, pyramid?)
                axesDesc = (chartTypes.length === 1 && chartTypes[0] === 'pie' || chartTypes[0] === 'map') && {} || chart.getAxesDescription(),
                chartTypeInfo = series[0] && typeToSeriesMap[series[0].type] || typeToSeriesMap.default;

            hiddenSection.setAttribute('role', 'region');
            hiddenSection.setAttribute('aria-label', 'Chart screen reader information.');

            hiddenSection.innerHTML = a11yOptions.screenReaderSectionFormatter && a11yOptions.screenReaderSectionFormatter(chart) ||
                '<div tabindex="0">Use regions/landmarks to skip ahead to chart' +
                (series.length > 1 ? ' and navigate between data series' : '') + '.</div><h3>Summary.</h3><div>' + (options.title.text || 'Chart') +
                (options.subtitle && options.subtitle.text ? '. ' + options.subtitle.text : '') +
                '</div><h3>Long description.</h3><div>' + (options.chart.description || 'No description available.') +
                '</div><h3>Structure.</h3><div>Chart type: ' + (options.chart.typeDescription || chart.getTypeDescription()) + '</div>' +
                (series.length === 1 ? '<div>' + chartTypeInfo[0] + ' with ' + series[0].points.length + ' ' +
                    (series[0].points.length === 1 ? chartTypeInfo[1] : chartTypeInfo[2]) + '.</div>' : '') +
                (axesDesc.xAxis ? ('<div>' + axesDesc.xAxis + '</div>') : '') +
                (axesDesc.yAxis ? ('<div>' + axesDesc.yAxis + '</div>') : '');

            // Add shortcut to data table if export-csv is loaded
            if (chart.getCSV) {
                tableShortcutAnchor.innerHTML = 'View as data table.';
                tableShortcutAnchor.href = '#' + tableId;
                tableShortcutAnchor.setAttribute('tabindex', '-1'); // Make this unreachable by user tabbing
                tableShortcutAnchor.onclick = a11yOptions.onTableAnchorClick || function() {
                    chart.viewData();
                    doc.getElementById(tableId).focus();
                };
                tableShortcut.appendChild(tableShortcutAnchor);

                hiddenSection.appendChild(tableShortcut);
            }

            chartHeading.innerHTML = 'Chart graphic.';
            chart.renderTo.insertBefore(chartHeading, chart.renderTo.firstChild);
            chart.renderTo.insertBefore(hiddenSection, chart.renderTo.firstChild);

            // Hide the section and the chart heading
            merge(true, chartHeading.style, hiddenStyle);
            merge(true, hiddenSection.style, hiddenStyle);
        };


        // Make chart container accessible, and wrap table functionality
        H.Chart.prototype.callbacks.push(function(chart) {
            var options = chart.options,
                a11yOptions = options.accessibility;

            if (!a11yOptions.enabled) {
                return;
            }

            var titleElement = doc.createElementNS('http://www.w3.org/2000/svg', 'title'),
                exportGroupElement = doc.createElementNS('http://www.w3.org/2000/svg', 'g'),
                descElement = chart.container.getElementsByTagName('desc')[0],
                textElements = chart.container.getElementsByTagName('text'),
                titleId = 'highcharts-title-' + chart.index,
                tableId = 'highcharts-data-table-' + chart.index,
                chartTitle = options.title.text || 'Chart',
                oldColumnHeaderFormatter = options.exporting && options.exporting.csv && options.exporting.csv.columnHeaderFormatter,
                topLevelColumns = [];

            // Add SVG title/desc tags
            titleElement.textContent = chartTitle;
            titleElement.id = titleId;
            descElement.parentNode.insertBefore(titleElement, descElement);
            chart.renderTo.setAttribute('role', 'region');
            chart.renderTo.setAttribute('aria-label', chartTitle + '. Use up and down arrows to navigate.');

            // Set screen reader properties on export menu
            if (chart.exportSVGElements && chart.exportSVGElements[0] && chart.exportSVGElements[0].element) {
                var oldExportCallback = chart.exportSVGElements[0].element.onclick,
                    parent = chart.exportSVGElements[0].element.parentNode;
                chart.exportSVGElements[0].element.onclick = function() {
                    oldExportCallback.apply(this, Array.prototype.slice.call(arguments));
                    chart.addAccessibleContextMenuAttribs();
                    chart.highlightExportItem(0);
                };
                chart.exportSVGElements[0].element.setAttribute('role', 'button');
                chart.exportSVGElements[0].element.setAttribute('aria-label', 'View export menu');
                exportGroupElement.appendChild(chart.exportSVGElements[0].element);
                exportGroupElement.setAttribute('role', 'region');
                exportGroupElement.setAttribute('aria-label', 'Chart export menu');
                parent.appendChild(exportGroupElement);
            }

            // Set screen reader properties on input boxes for range selector. We need to do this regardless of whether or not these are visible, as they are 
            // by default part of the page's tabindex unless we set them to -1.
            if (chart.rangeSelector) {
                each(['minInput', 'maxInput'], function(key, i) {
                    if (chart.rangeSelector[key]) {
                        chart.rangeSelector[key].setAttribute('tabindex', '-1');
                        chart.rangeSelector[key].setAttribute('role', 'textbox');
                        chart.rangeSelector[key].setAttribute('aria-label', 'Select ' + (i ? 'end' : 'start') + ' date.');
                    }
                });
            }

            // Hide text elements from screen readers
            each(textElements, function(el) {
                el.setAttribute('aria-hidden', 'true');
            });

            // Add top-secret screen reader region
            chart.addScreenReaderRegion(tableId);

            // Enable keyboard navigation
            if (a11yOptions.keyboardNavigation) {
                chart.addKeyboardNavEvents();
            }

            /* Wrap table functionality from export-csv */

            // Keep track of columns
            merge(true, options.exporting, {
                csv: {
                    columnHeaderFormatter: function(series, key, keyLength) {
                        var prevCol = topLevelColumns[topLevelColumns.length - 1];
                        if (keyLength > 1) {
                            // We need multiple levels of column headers
                            // Populate a list of column headers to add in addition to the ones added by export-csv
                            if ((prevCol && prevCol.text) !== series.name) {
                                topLevelColumns.push({
                                    text: series.name,
                                    span: keyLength
                                });
                            }
                        }
                        if (oldColumnHeaderFormatter) {
                            return oldColumnHeaderFormatter.call(this, series, key, keyLength);
                        }
                        return keyLength > 1 ? key : series.name;
                    }
                }
            });

            // Add ID and title/caption to table HTML
            H.wrap(chart, 'getTable', function(proceed) {
                return proceed.apply(this, Array.prototype.slice.call(arguments, 1))
                    .replace('<table>', '<table id="' + tableId + '" summary="Table representation of chart"><caption>' + chartTitle + '</caption>');
            });

            // Add accessibility attributes and top level columns
            H.wrap(chart, 'viewData', function(proceed) {
                if (!this.insertedTable) {
                    proceed.apply(this, Array.prototype.slice.call(arguments, 1));

                    var table = doc.getElementById(tableId),
                        body = table.getElementsByTagName('tbody')[0],
                        firstRow = body.firstChild.children,
                        columnHeaderRow = '<tr><td></td>',
                        cell,
                        newCell;

                    // Make table focusable by script
                    table.setAttribute('tabindex', '-1');

                    // Create row headers
                    each(body.children, function(el) {
                        cell = el.firstChild;
                        newCell = doc.createElement('th');
                        newCell.setAttribute('scope', 'row');
                        newCell.innerHTML = cell.innerHTML;
                        cell.parentNode.replaceChild(newCell, cell);
                    });

                    // Set scope for column headers
                    each(firstRow, function(el) {
                        if (el.tagName === 'TH') {
                            el.setAttribute('scope', 'col');
                        }
                    });

                    // Add top level columns
                    if (topLevelColumns.length) {
                        each(topLevelColumns, function(col) {
                            columnHeaderRow += '<th scope="col" colspan="' + col.span + '">' + col.text + '</th>';
                        });
                        body.insertAdjacentHTML('afterbegin', columnHeaderRow);
                    }
                }
            });
        });

    }(Highcharts));
}));