/**
 * @license Highcharts JS v6.1.3 (2018-09-12)
 * Accessibility module
 *
 * (c) 2010-2017 Highsoft AS
 * Author: Oystein Moseng
 *
 * License: www.highcharts.com/license
 */
'use strict';
(function (factory) {
	if (typeof module === 'object' && module.exports) {
		module.exports = factory;
	} else if (typeof define === 'function' && define.amd) {
		define(function () {
			return factory;
		});
	} else {
		factory(Highcharts);
	}
}(function (Highcharts) {
	(function (H) {
		/**
		 * Accessibility module - internationalization support
		 *
		 * (c) 2010-2018 Highsoft AS
		 * Author: Øystein Moseng
		 *
		 * License: www.highcharts.com/license
		 */


		var each = H.each,
		    pick = H.pick;

		/**
		 * String trim that works for IE6-8 as well.
		 * @param  {string} str The input string
		 * @return {string} The trimmed string
		 */
		function stringTrim(str) {
		    return str.trim && str.trim() || str.replace(/^\s+|\s+$/g, '');
		}

		/**
		 * i18n utility function. Format a single array or plural statement in a format
		 * string. If the statement is not an array or plural statement, returns the
		 * statement within brackets. Invalid array statements return an empty string.
		 */
		function formatExtendedStatement(statement, ctx) {
		    var eachStart = statement.indexOf('#each('),
		        pluralStart = statement.indexOf('#plural('),
		        indexStart = statement.indexOf('['),
		        indexEnd = statement.indexOf(']'),
		        arr,
		        result;

		    // Dealing with an each-function?
		    if (eachStart > -1) {
		        var eachEnd = statement.slice(eachStart).indexOf(')') + eachStart,
		            preEach = statement.substring(0, eachStart),
		            postEach = statement.substring(eachEnd + 1),
		            eachStatement = statement.substring(eachStart + 6, eachEnd),
		            eachArguments = eachStatement.split(','),
		            lenArg = Number(eachArguments[1]),
		            len;
		        result = '';
		        arr = ctx[eachArguments[0]];
		        if (arr) {
		            lenArg = isNaN(lenArg) ? arr.length : lenArg;
		            len = lenArg < 0 ?
		                arr.length + lenArg :
		                Math.min(lenArg, arr.length); // Overshoot
		            // Run through the array for the specified length
		            for (var i = 0; i < len; ++i) {
		                result += preEach + arr[i] + postEach;
		            }
		        }
		        return result.length ? result : '';
		    }

		    // Dealing with a plural-function?
		    if (pluralStart > -1) {
		        var pluralEnd = statement.slice(pluralStart).indexOf(')') + pluralStart,
		            pluralStatement = statement.substring(pluralStart + 8, pluralEnd),
		            pluralArguments = pluralStatement.split(','),
		            num = Number(ctx[pluralArguments[0]]);
		        switch (num) {
		            case 0:
		                result = pick(pluralArguments[4], pluralArguments[1]);
		                break;
		            case 1:
		                result = pick(pluralArguments[2], pluralArguments[1]);
		                break;
		            case 2:
		                result = pick(pluralArguments[3], pluralArguments[1]);
		                break;
		            default:
		                result = pluralArguments[1];
		        }
		        return result ? stringTrim(result) : '';
		    }

		    // Array index
		    if (indexStart > -1) {
		        var arrayName = statement.substring(0, indexStart),
		            ix = Number(statement.substring(indexStart + 1, indexEnd)),
		            val;
		        arr = ctx[arrayName];
		        if (!isNaN(ix) && arr) {
		            if (ix < 0) {
		                val = arr[arr.length + ix];
		                // Handle negative overshoot
		                if (val === undefined) {
		                    val = arr[0];
		                }
		            } else {
		                val = arr[ix];
		                // Handle positive overshoot
		                if (val === undefined) {
		                    val = arr[arr.length - 1];
		                }
		            }
		        }
		        return val !== undefined ? val : '';
		    }

		    // Standard substitution, delegate to H.format or similar
		    return '{' + statement + '}';
		}


		/**
		 * i18n formatting function. Extends H.format() functionality by also handling
		 * arrays and plural conditionals. Arrays can be indexed as follows:
		 *
		 *  Format: 'This is the first index: {myArray[0]}. The last: {myArray[-1]}.'
		 *  Context: { myArray: [0, 1, 2, 3, 4, 5] }
		 *  Result: 'This is the first index: 0. The last: 5.'
		 *
		 * They can also be iterated using the #each() function. This will repeat the
		 * contents of the bracket expression for each element. Example:
		 *
		 *  Format: 'List contains: {#each(myArray)cm }'
		 *  Context: { myArray: [0, 1, 2] }
		 *  Result: 'List contains: 0cm 1cm 2cm '
		 *
		 * The #each() function optionally takes a length parameter. If positive, this
		 * parameter specifies the max number of elements to iterate through. If
		 * negative, the function will subtract the number from the length of the array.
		 * Use this to stop iterating before the array ends. Example:
		 *
		 *  Format: 'List contains: {#each(myArray, -1) }and {myArray[-1]}.'
		 *  Context: { myArray: [0, 1, 2, 3] }
		 *  Result: 'List contains: 0, 1, 2, and 3.'
		 *
		 * Use the #plural() function to pick a string depending on whether or not a
		 * context object is 1. Arguments are #plural(obj, plural, singular). Example:
		 *
		 *  Format: 'Has {numPoints} {#plural(numPoints, points, point}.'
		 *  Context: { numPoints: 5 }
		 *  Result: 'Has 5 points.'
		 *
		 * Optionally there are additional parameters for dual and none:
		 *  #plural(obj,plural,singular,dual,none)
		 * Example:
		 *
		 *  Format: 'Has {#plural(numPoints, many points, one point, two points, none}.'
		 *  Context: { numPoints: 2 }
		 *  Result: 'Has two points.'
		 *
		 * The dual or none parameters will take precedence if they are supplied.
		 *
		 * @param   {string} formatString The string to format.
		 * @param   {object} context Context to apply to the format string.
		 * @param   {Time} time A `Time` instance for date formatting, passed on to
		 *                 H.format().
		 * @return  {string} The formatted string.
		 */
		H.i18nFormat = function (formatString, context, time) {
		    var getFirstBracketStatement = function (sourceStr, offset) {
		            var str = sourceStr.slice(offset || 0),
		                startBracket = str.indexOf('{'),
		                endBracket = str.indexOf('}');
		            if (startBracket > -1 && endBracket > startBracket) {
		                return {
		                    statement: str.substring(startBracket + 1, endBracket),
		                    begin: offset + startBracket + 1,
		                    end: offset + endBracket
		                };
		            }
		        },
		        tokens = [],
		        bracketRes,
		        constRes,
		        cursor = 0;

		    // Tokenize format string into bracket statements and constants
		    do {
		        bracketRes = getFirstBracketStatement(formatString, cursor);
		        constRes = formatString.substring(
		            cursor,
		            bracketRes && bracketRes.begin - 1
		        );

		        // If we have constant content before this bracket statement, add it
		        if (constRes.length) {
		            tokens.push({
		                value: constRes,
		                type: 'constant'
		            });
		        }

		        // Add the bracket statement
		        if (bracketRes) {
		            tokens.push({
		                value: bracketRes.statement,
		                type: 'statement'
		            });
		        }

		        cursor = bracketRes && bracketRes.end + 1;
		    } while (bracketRes);

		    // Perform the formatting. The formatArrayStatement function returns the
		    // statement in brackets if it is not an array statement, which means it
		    // gets picked up by H.format below.
		    each(tokens, function (token) {
		        if (token.type === 'statement') {
		            token.value = formatExtendedStatement(token.value, context);
		        }
		    });

		    // Join string back together and pass to H.format to pick up non-array
		    // statements.
		    return H.format(H.reduce(tokens, function (acc, cur) {
		        return acc + cur.value;
		    }, ''), context, time);
		};


		/**
		 * Apply context to a format string from lang options of the chart.
		 * @param  {string} langKey Key (using dot notation) into lang option structure
		 * @param  {object} context Context to apply to the format string
		 * @return {string} The formatted string
		 */
		H.Chart.prototype.langFormat = function (langKey, context, time) {
		    var keys = langKey.split('.'),
		        formatString = this.options.lang,
		        i = 0;
		    for (; i < keys.length; ++i) {
		        formatString = formatString && formatString[keys[i]];
		    }
		    return typeof formatString === 'string' && H.i18nFormat(
		        formatString, context, time
		    );
		};

		H.setOptions({
		    lang: {
		        /**
		         * Configure the accessibility strings in the chart. Requires the
		         * [accessibility module](//code.highcharts.com/modules/accessibility.
		         * js) to be loaded. For a description of the module and information
		         * on its features, see [Highcharts Accessibility](http://www.highcharts.
		         * com/docs/chart-concepts/accessibility).
		         *
		         * For more dynamic control over the accessibility functionality, see
		         * [accessibility.pointDescriptionFormatter](
		         * accessibility.pointDescriptionFormatter),
		         * [accessibility.seriesDescriptionFormatter](
		         * accessibility.seriesDescriptionFormatter), and
		         * [accessibility.screenReaderSectionFormatter](
		         * accessibility.screenReaderSectionFormatter).
		         *
		         * @since 6.0.6
		         * @type {Object}
		         * @optionparent lang.accessibility
		         */
		        accessibility: {
		            /* eslint-disable max-len */

		            screenReaderRegionLabel: 'Chart screen reader information.',
		            navigationHint: 'Use regions/landmarks to skip ahead to chart {#plural(numSeries, and navigate between data series,)}',
		            defaultChartTitle: 'Chart',
		            longDescriptionHeading: 'Long description.',
		            noDescription: 'No description available.',
		            structureHeading: 'Structure.',
		            viewAsDataTable: 'View as data table.',
		            chartHeading: 'Chart graphic.',
		            chartContainerLabel: 'Interactive chart. {title}. Use up and down arrows to navigate with most screen readers.',
		            rangeSelectorMinInput: 'Select start date.',
		            rangeSelectorMaxInput: 'Select end date.',
		            tableSummary: 'Table representation of chart.',
		            mapZoomIn: 'Zoom chart',
		            mapZoomOut: 'Zoom out chart',
		            rangeSelectorButton: 'Select range {buttonText}',
		            legendItem: 'Toggle visibility of series {itemName}',

		            /**
		             * Title element text for the chart SVG element. Leave this
		             * empty to disable adding the title element. Browsers will display
		             * this content when hovering over elements in the chart. Assistive
		             * technology may use this element to label the chart.
		             *
		             * @since 6.0.8
		             */
		            svgContainerTitle: '{chartTitle}',

		            /**
		             * Descriptions of lesser known series types. The relevant
		             * description is added to the screen reader information region
		             * when these series types are used.
		             *
		             * @since 6.0.6
		             * @type {Object}
		             * @optionparent lang.accessibility.seriesTypeDescriptions
		             */
		            seriesTypeDescriptions: {
		                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.'
		            },

		            /**
		             * Chart type description strings. This is added to the chart
		             * information region.
		             *
		             * If there is only a single series type used in the chart, we use
		             * the format string for the series type, or default if missing.
		             * There is one format string for cases where there is only a single
		             * series in the chart, and one for multiple series of the same
		             * type.
		             *
		             * @since 6.0.6
		             * @type {Object}
		             * @optionparent lang.accessibility.chartTypes
		             */
		            chartTypes: {
		                emptyChart: 'Empty chart',
		                mapTypeDescription: 'Map of {mapTitle} with {numSeries} data series.',
		                unknownMap: 'Map of unspecified region with {numSeries} data series.',
		                combinationChart: 'Combination chart with {numSeries} data series.',
		                defaultSingle: 'Chart with {numPoints} data {#plural(numPoints, points, point)}.',
		                defaultMultiple: 'Chart with {numSeries} data series.',
		                splineSingle: 'Line chart with {numPoints} data {#plural(numPoints, points, point)}.',
		                splineMultiple: 'Line chart with {numSeries} lines.',
		                lineSingle: 'Line chart with {numPoints} data {#plural(numPoints, points, point)}.',
		                lineMultiple: 'Line chart with {numSeries} lines.',
		                columnSingle: 'Bar chart with {numPoints} {#plural(numPoints, bars, bar)}.',
		                columnMultiple: 'Bar chart with {numSeries} data series.',
		                barSingle: 'Bar chart with {numPoints} {#plural(numPoints, bars, bar)}.',
		                barMultiple: 'Bar chart with {numSeries} data series.',
		                pieSingle: 'Pie chart with {numPoints} {#plural(numPoints, slices, slice)}.',
		                pieMultiple: 'Pie chart with {numSeries} pies.',
		                scatterSingle: 'Scatter chart with {numPoints} {#plural(numPoints, points, point)}.',
		                scatterMultiple: 'Scatter chart with {numSeries} data series.',
		                boxplotSingle: 'Boxplot with {numPoints} {#plural(numPoints, boxes, box)}.',
		                boxplotMultiple: 'Boxplot with {numSeries} data series.',
		                bubbleSingle: 'Bubble chart with {numPoints} {#plural(numPoints, bubbles, bubble)}.',
		                bubbleMultiple: 'Bubble chart with {numSeries} data series.'
		            },

		            /**
		             * Axis description format strings.
		             *
		             * @since 6.0.6
		             * @type {Object}
		             * @optionparent lang.accessibility.axis
		             */
		            axis: {
		                xAxisDescriptionSingular: 'The chart has 1 X axis displaying {names[0]}.',
		                xAxisDescriptionPlural: 'The chart has {numAxes} X axes displaying {#each(names, -1) }and {names[-1]}',
		                yAxisDescriptionSingular: 'The chart has 1 Y axis displaying {names[0]}.',
		                yAxisDescriptionPlural: 'The chart has {numAxes} Y axes displaying {#each(names, -1) }and {names[-1]}'
		            },

		            /**
		             * Exporting menu format strings for accessibility module.
		             *
		             * @since 6.0.6
		             * @type {Object}
		             * @optionparent lang.accessibility.exporting
		             */
		            exporting: {
		                chartMenuLabel: 'Chart export',
		                menuButtonLabel: 'View export menu',
		                exportRegionLabel: 'Chart export menu'
		            },

		            /**
		             * Lang configuration for different series types. For more dynamic
		             * control over the series element descriptions, see
		             * [accessibility.seriesDescriptionFormatter](
		             * accessibility.seriesDescriptionFormatter).
		             *
		             * @since 6.0.6
		             * @type {Object}
		             * @optionparent lang.accessibility.series
		             */
		            series: {
		                /**
		                 * Lang configuration for the series main summary. Each series
		                 * type has two modes:
		                 *     1. This series type is the only series type used in the
		                 *        chart
		                 *    2. This is a combination chart with multiple series types
		                 *
		                 * If a definition does not exist for the specific series type
		                 * and mode, the 'default' lang definitions are used.
		                 *
		                 * @since 6.0.6
		                 * @type {Object}
		                 * @optionparent lang.accessibility.series.summary
		                 */
		                summary: {
		                    default: '{name}, series {ix} of {numSeries} with {numPoints} data {#plural(numPoints, points, point)}.',
		                    defaultCombination: '{name}, series {ix} of {numSeries} with {numPoints} data {#plural(numPoints, points, point)}.',
		                    line: '{name}, line {ix} of {numSeries} with {numPoints} data {#plural(numPoints, points, point)}.',
		                    lineCombination: '{name}, series {ix} of {numSeries}. Line with {numPoints} data {#plural(numPoints, points, point)}.',
		                    spline: '{name}, line {ix} of {numSeries} with {numPoints} data {#plural(numPoints, points, point)}.',
		                    splineCombination: '{name}, series {ix} of {numSeries}. Line with {numPoints} data {#plural(numPoints, points, point)}.',
		                    column: '{name}, bar series {ix} of {numSeries} with {numPoints} {#plural(numPoints, bars, bar)}.',
		                    columnCombination: '{name}, series {ix} of {numSeries}. Bar series with {numPoints} {#plural(numPoints, bars, bar)}.',
		                    bar: '{name}, bar series {ix} of {numSeries} with {numPoints} {#plural(numPoints, bars, bar)}.',
		                    barCombination: '{name}, series {ix} of {numSeries}. Bar series with {numPoints} {#plural(numPoints, bars, bar)}.',
		                    pie: '{name}, pie {ix} of {numSeries} with {numPoints} {#plural(numPoints, slices, slice)}.',
		                    pieCombination: '{name}, series {ix} of {numSeries}. Pie with {numPoints} {#plural(numPoints, slices, slice)}.',
		                    scatter: '{name}, scatter plot {ix} of {numSeries} with {numPoints} {#plural(numPoints, points, point)}.',
		                    scatterCombination: '{name}, series {ix} of {numSeries}, scatter plot with {numPoints} {#plural(numPoints, points, point)}.',
		                    boxplot: '{name}, boxplot {ix} of {numSeries} with {numPoints} {#plural(numPoints, boxes, box)}.',
		                    boxplotCombination: '{name}, series {ix} of {numSeries}. Boxplot with {numPoints} {#plural(numPoints, boxes, box)}.',
		                    bubble: '{name}, bubble series {ix} of {numSeries} with {numPoints} {#plural(numPoints, bubbles, bubble)}.',
		                    bubbleCombination: '{name}, series {ix} of {numSeries}. Bubble series with {numPoints} {#plural(numPoints, bubbles, bubble)}.',
		                    map: '{name}, map {ix} of {numSeries} with {numPoints} {#plural(numPoints, areas, area)}.',
		                    mapCombination: '{name}, series {ix} of {numSeries}. Map with {numPoints} {#plural(numPoints, areas, area)}.',
		                    mapline: '{name}, line {ix} of {numSeries} with {numPoints} data {#plural(numPoints, points, point)}.',
		                    maplineCombination: '{name}, series {ix} of {numSeries}. Line with {numPoints} data {#plural(numPoints, points, point)}.',
		                    mapbubble: '{name}, bubble series {ix} of {numSeries} with {numPoints} {#plural(numPoints, bubbles, bubble)}.',
		                    mapbubbleCombination: '{name}, series {ix} of {numSeries}. Bubble series with {numPoints} {#plural(numPoints, bubbles, bubble)}.'
		                },
		                /* eslint-enable max-len */

		                /**
		                 * User supplied description text. This is added after the main
		                 * summary if present.
		                 *
		                 * @type {String}
		                 * @since 6.0.6
		                 */
		                description: '{description}',

		                /**
		                 * xAxis description for series if there are multiple xAxes in
		                 * the chart.
		                 *
		                 * @type {String}
		                 * @since 6.0.6
		                 */
		                xAxisDescription: 'X axis, {name}',

		                /**
		                 * yAxis description for series if there are multiple yAxes in
		                 * the chart.
		                 *
		                 * @type {String}
		                 * @since 6.0.6
		                 */
		                yAxisDescription: 'Y axis, {name}'
		            }
		        }
		    }
		});

	}(Highcharts));
	(function (H) {
		/**
		 * Accessibility module - Screen Reader support
		 *
		 * (c) 2010-2017 Highsoft AS
		 * Author: Oystein Moseng
		 *
		 * License: www.highcharts.com/license
		 */


		var win = H.win,
		    doc = win.document,
		    each = H.each,
		    map = H.map,
		    erase = H.erase,
		    addEvent = H.addEvent,
		    merge = H.merge,
		    // CSS style to hide element from visual users while still exposing it to
		    // screen readers
		    hiddenStyle = {
		        position: 'absolute',
		        left: '-9999px',
		        top: 'auto',
		        width: '1px',
		        height: '1px',
		        overflow: 'hidden'
		    };

		// If a point has one of the special keys defined, we expose all keys to the
		// screen reader.
		H.Series.prototype.commonKeys = ['name', 'id', 'category', 'x', 'value', 'y'];
		H.Series.prototype.specialKeys = [
		    'z', 'open', 'high', 'q3', 'median', 'q1', 'low', 'close'
		];
		if (H.seriesTypes.pie) {
		    // A pie is always simple. Don't quote me on that.
		    H.seriesTypes.pie.prototype.specialKeys = [];
		}


		/**
		 * HTML encode some characters vulnerable for XSS.
		 * @param  {string} html The input string
		 * @return {string} The excaped string
		 */
		function htmlencode(html) {
		    return html
		        .replace(/&/g, '&amp;')
		        .replace(/</g, '&lt;')
		        .replace(/>/g, '&gt;')
		        .replace(/"/g, '&quot;')
		        .replace(/'/g, '&#x27;')
		        .replace(/\//g, '&#x2F;');
		}


		/**
		 * Strip HTML tags away from a string. Used for aria-label attributes, painting
		 * on a canvas will fail if the text contains tags.
		 * @param  {String} s The input string
		 * @return {String}   The filtered string
		 */
		function stripTags(s) {
		    return typeof s === 'string' ? s.replace(/<\/?[^>]+(>|$)/g, '') : s;
		}


		/**
		 * Accessibility options
		 */
		H.setOptions({

		    /**
		     * Options for configuring accessibility for the chart. Requires the
		     * [accessibility module](//code.highcharts.com/modules/accessibility.
		     * js) to be loaded. For a description of the module and information
		     * on its features, see [Highcharts Accessibility](http://www.highcharts.
		     * com/docs/chart-concepts/accessibility).
		     *
		     * @since 5.0.0
		     * @type {Object}
		     * @optionparent accessibility
		     */
		    accessibility: {

		        /**
		         * Whether or not to add series descriptions to charts with a single
		         * series.
		         *
		         * @type {Boolean}
		         * @default false
		         * @since 5.0.0
		         * @apioption accessibility.describeSingleSeries
		         */

		        /**
		         * Function to run upon clicking the "View as Data Table" link in the
		         * screen reader region.
		         *
		         * By default Highcharts will insert and set focus to a data table
		         * representation of the chart.
		         *
		         * @type {Function}
		         * @since 5.0.0
		         * @apioption accessibility.onTableAnchorClick
		         */

		        /**
		         * Date format to use for points on datetime axes when describing them
		         * to screen reader users.
		         *
		         * Defaults to the same format as in tooltip.
		         *
		         * For an overview of the replacement codes, see
		         * [dateFormat](/class-reference/Highcharts#dateFormat).
		         *
		         * @type {String}
		         * @see [pointDateFormatter](#accessibility.pointDateFormatter)
		         * @since 5.0.0
		         * @apioption accessibility.pointDateFormat
		         */

		        /**
		         * Formatter function to determine the date/time format used with
		         * points on datetime axes when describing them to screen reader users.
		         * Receives one argument, `point`, referring to the point to describe.
		         * Should return a date format string compatible with
		         * [dateFormat](/class-reference/Highcharts#dateFormat).
		         *
		         * @type {Function}
		         * @see [pointDateFormat](#accessibility.pointDateFormat)
		         * @since 5.0.0
		         * @apioption accessibility.pointDateFormatter
		         */

		        /**
		         * Formatter function to use instead of the default for point
		         * descriptions.
		         * Receives one argument, `point`, referring to the point to describe.
		         * Should return a String with the description of the point for a screen
		         * reader user.
		         *
		         * @type {Function}
		         * @see [point.description](#series.line.data.description)
		         * @since 5.0.0
		         * @apioption accessibility.pointDescriptionFormatter
		         */

		        /**
		         * Formatter function to use instead of the default for series
		         * descriptions. Receives one argument, `series`, referring to the
		         * series to describe. Should return a String with the description of
		         * the series for a screen reader user.
		         *
		         * @type {Function}
		         * @see [series.description](#plotOptions.series.description)
		         * @since 5.0.0
		         * @apioption accessibility.seriesDescriptionFormatter
		         */

		        /**
		         * Enable accessibility features for the chart.
		         *
		         * @type {Boolean}
		         * @default true
		         * @since 5.0.0
		         */
		        enabled: true,

		        /**
		         * When a series contains more points than this, we no longer expose
		         * information about individual points to screen readers.
		         *
		         * Set to `false` to disable.
		         *
		         * @type {Number|Boolean}
		         * @since 5.0.0
		         */
		        pointDescriptionThreshold: false, // set to false to disable

		        /**
		         * A formatter function to create the HTML contents of the hidden screen
		         * reader information region. Receives one argument, `chart`, referring
		         * to the chart object. Should return a String with the HTML content
		         * of the region.
		         *
		         * The link to view the chart as a data table will be added
		         * automatically after the custom HTML content.
		         *
		         * @type {Function}
		         * @default undefined
		         * @since 5.0.0
		         */
		        screenReaderSectionFormatter: function (chart) {
		            var options = chart.options,
		                chartTypes = chart.types || [],
		                formatContext = {
		                    chart: chart,
		                    numSeries: chart.series && chart.series.length
		                },
		                // 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();

		            return '<div>' + chart.langFormat(
		                        'accessibility.navigationHint', formatContext
		                    ) + '</div><h3>' +
		                    (
		                        options.title.text ?
		                            htmlencode(options.title.text) :
		                            chart.langFormat(
		                                'accessibility.defaultChartTitle', formatContext
		                            )
		                    ) +
		                    (
		                        options.subtitle && options.subtitle.text ?
		                            '. ' + htmlencode(options.subtitle.text) :
		                            ''
		                    ) +
		                    '</h3><h4>' + chart.langFormat(
		                        'accessibility.longDescriptionHeading', formatContext
		                    ) + '</h4><div>' +
		                    (
		                        options.chart.description || chart.langFormat(
		                            'accessibility.noDescription', formatContext
		                        )
		                    ) +
		                    '</div><h4>' + chart.langFormat(
		                        'accessibility.structureHeading', formatContext
		                    ) + '</h4><div>' +
		                    (
		                        options.chart.typeDescription ||
		                        chart.getTypeDescription()
		                    ) + '</div>' +
		                    (axesDesc.xAxis ? (
		                        '<div>' + axesDesc.xAxis + '</div>'
		                    ) : '') +
		                    (axesDesc.yAxis ? (
		                        '<div>' + axesDesc.yAxis + '</div>'
		                    ) : '');
		        }
		    }
		});

		/**
		 * A text description of the chart.
		 *
		 * If the Accessibility module is loaded, this is included by default
		 * as a long description of the chart and its contents in the hidden
		 * screen reader information region.
		 *
		 * @type {String}
		 * @see [typeDescription](#chart.typeDescription)
		 * @default undefined
		 * @since 5.0.0
		 * @apioption chart.description
		 */

		 /**
		 * A text description of the chart type.
		 *
		 * If the Accessibility module is loaded, this will be included in the
		 * description of the chart in the screen reader information region.
		 *
		 *
		 * Highcharts will by default attempt to guess the chart type, but for
		 * more complex charts it is recommended to specify this property for
		 * clarity.
		 *
		 * @type {String}
		 * @default undefined
		 * @since 5.0.0
		 * @apioption chart.typeDescription
		 */


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


		// Whenever drawing series, put info on DOM elements
		H.addEvent(H.Series, 'afterRender', function () {
		    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', stripTags(
		                        point.series.options.pointDescriptionFormatter &&
		                        point.series.options.pointDescriptionFormatter(point) ||
		                        a11yOptions.pointDescriptionFormatter &&
		                        a11yOptions.pointDescriptionFormatter(point) ||
		                        point.buildPointInfoString()
		                    ));
		                }
		            });
		        }
		        // Make series element accessible
		        if (this.chart.series.length > 1 || a11yOptions.describeSingleSeries) {
		            seriesEl.setAttribute(
		                'role',
		                this.options.exposeElementToA11y ? 'img' : 'region'
		            );
		            seriesEl.setAttribute('tabindex', '-1');
		            seriesEl.setAttribute(
		                'aria-label',
		                stripTags(
		                    a11yOptions.seriesDescriptionFormatter &&
		                    a11yOptions.seriesDescriptionFormatter(this) ||
		                    this.buildSeriesInfoString()
		                )
		            );
		        }
		    }
		};


		// Return string with information about series
		H.Series.prototype.buildSeriesInfoString = function () {
		    var chart = this.chart,
		        desc = this.description || this.options.description,
		        description = desc && chart.langFormat(
		            'accessibility.series.description', {
		                description: desc,
		                series: this
		            }
		        ),
		        xAxisInfo = chart.langFormat(
		            'accessibility.series.xAxisDescription',
		            {
		                name: this.xAxis && this.xAxis.getDescription(),
		                series: this
		            }
		        ),
		        yAxisInfo = chart.langFormat(
		            'accessibility.series.yAxisDescription',
		            {
		                name: this.yAxis && this.yAxis.getDescription(),
		                series: this
		            }
		        ),
		        summaryContext = {
		            name: this.name || '',
		            ix: this.index + 1,
		            numSeries: chart.series.length,
		            numPoints: this.points.length,
		            series: this
		        },
		        combination = chart.types.length === 1 ? '' : 'Combination',
		        summary = chart.langFormat(
		            'accessibility.series.summary.' + this.type + combination,
		            summaryContext
		        ) || chart.langFormat(
		            'accessibility.series.summary.default' + combination,
		            summaryContext
		        );

		    return summary + (description ? ' ' + description : '') + (
		            chart.yAxis.length > 1 && this.yAxis ?
		                ' ' + yAxisInfo : ''
		        ) + (
		            chart.xAxis.length > 1 && this.xAxis ?
		                ' ' + xAxisInfo : ''
		        );
		};


		// Return string with information about point
		H.Point.prototype.buildPointInfoString = function () {
		    var point = this,
		        series = point.series,
		        a11yOptions = series.chart.options.accessibility,
		        infoString = '',
		        dateTimePoint = series.xAxis && series.xAxis.isDatetimeAxis,
		        timeDesc =
		            dateTimePoint &&
		            series.chart.time.dateFormat(
		                a11yOptions.pointDateFormatter &&
		                a11yOptions.pointDateFormatter(point) ||
		                a11yOptions.pointDateFormat ||
		                H.Tooltip.prototype.getXDateFormat.call(
		                    {
		                        getDateFormat: H.Tooltip.prototype.getDateFormat,
		                        chart: series.chart
		                    },
		                    point,
		                    series.chart.options.tooltip,
		                    series.xAxis
		                ),
		                point.x
		            ),
		        hasSpecialKey = H.find(series.specialKeys, function (key) {
		            return point[key] !== undefined;
		        });

		    // If the point has one of the less common properties defined, display all
		    // that are defined
		    if (hasSpecialKey) {
		        if (dateTimePoint) {
		            infoString = timeDesc;
		        }
		        each(series.commonKeys.concat(series.specialKeys), function (key) {
		            if (point[key] !== undefined && !(dateTimePoint && key === 'x')) {
		                infoString += (infoString ? '. ' : '') +
		                    key + ', ' +
		                    point[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' ||
		        this.isDatetimeAxis && 'Time' ||
		        'values'
		    );
		};


		// Whenever adding or removing series, keep track of types present in chart
		addEvent(H.Series, 'afterInit', function () {
		    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(H.Series, 'remove', function () {
		    var chart = this.chart,
		        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 in those cases we try to add a description
		// of the type.
		H.Chart.prototype.getTypeDescription = function () {
		    var firstType = this.types && this.types[0],
		        firstSeries = this.series && this.series[0] || {},
		        mapTitle = firstSeries.mapTitle,
		        typeDesc = this.langFormat(
		            'accessibility.seriesTypeDescriptions.' + firstType,
		            { chart: this }
		        ),
		        formatContext = {
		            numSeries: this.series.length,
		            numPoints: firstSeries.points && firstSeries.points.length,
		            chart: this,
		            mapTitle: mapTitle
		        },
		        multi = this.series && this.series.length === 1 ? 'Single' : 'Multiple';

		    if (!firstType) {
		        return this.langFormat(
		            'accessibility.chartTypes.emptyChart', formatContext
		        );
		    } else if (firstType === 'map') {
		        return mapTitle ?
		            this.langFormat(
		                'accessibility.chartTypes.mapTypeDescription',
		                formatContext
		            ) :
		            this.langFormat(
		                'accessibility.chartTypes.unknownMap',
		                formatContext
		            );
		    } else if (this.types.length > 1) {
		        return this.langFormat(
		            'accessibility.chartTypes.combinationChart', formatContext
		        );
		    }

		    return (
		        this.langFormat(
		            'accessibility.chartTypes.' + firstType + multi,
		            formatContext
		        ) ||
		        this.langFormat(
		            'accessibility.chartTypes.default' + multi,
		            formatContext
		        )
		    ) +
		    (typeDesc ? ' ' + typeDesc : '');
		};


		// 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 = {};

		    if (numXAxes) {
		        desc.xAxis = this.langFormat(
		            'accessibility.axis.xAxisDescription' + (
		                numXAxes > 1 ? 'Plural' : 'Singular'
		            ),
		            {
		                chart: this,
		                names: map(this.xAxis, function (axis) {
		                    return axis.getDescription();
		                }),
		                numAxes: numXAxes
		            }
		        );
		    }

		    if (numYAxes) {
		        desc.yAxis = this.langFormat(
		            'accessibility.axis.yAxisDescription' + (
		                numYAxes > 1 ? 'Plural' : 'Singular'
		            ),
		            {
		                chart: this,
		                names: map(this.yAxis, function (axis) {
		                    return axis.getDescription();
		                }),
		                numAxes: numYAxes
		            }
		        );
		    }

		    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',
		            this.langFormat(
		                'accessibility.exporting.chartMenuLabel', { chart: this }
		            )
		        );
		    }
		};


		// 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 (id, tableId) {
		    var chart = this,
		        hiddenSection = chart.screenReaderRegion = doc.createElement('div'),
		        tableShortcut = doc.createElement('h4'),
		        tableShortcutAnchor = doc.createElement('a'),
		        chartHeading = doc.createElement('h4');

		    hiddenSection.setAttribute('id', id);
		    hiddenSection.setAttribute('role', 'region');
		    hiddenSection.setAttribute(
		        'aria-label',
		        chart.langFormat(
		            'accessibility.screenReaderRegionLabel', { chart: this }
		        )
		    );

		    hiddenSection.innerHTML = chart.options.accessibility
		        .screenReaderSectionFormatter(chart);

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

		    // Note: JAWS seems to refuse to read aria-label on the container, so add an
		    // h4 element as title for the chart.
		    chartHeading.innerHTML = chart.langFormat(
		        'accessibility.chartHeading', { chart: chart }
		    );
		    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,
		        descElement = chart.container.getElementsByTagName('desc')[0],
		        textElements = chart.container.getElementsByTagName('text'),
		        titleId = 'highcharts-title-' + chart.index,
		        tableId = 'highcharts-data-table-' + chart.index,
		        hiddenSectionId = 'highcharts-information-region-' + chart.index,
		        chartTitle = options.title.text || chart.langFormat(
		            'accessibility.defaultChartTitle', { chart: chart }
		        ),
		        svgContainerTitle = stripTags(chart.langFormat(
		            'accessibility.svgContainerTitle', {
		                chartTitle: chartTitle
		            }
		        ));

		    // Add SVG title tag if it is set
		    if (svgContainerTitle.length) {
		        titleElement = doc.createElementNS(
		                'http://www.w3.org/2000/svg',
		                'title'
		            );
		        titleElement.textContent = svgContainerTitle;
		        titleElement.id = titleId;
		        descElement.parentNode.insertBefore(titleElement, descElement);
		    }

		    chart.renderTo.setAttribute('role', 'region');
		    chart.renderTo.setAttribute(
		        'aria-label',
		        chart.langFormat(
		            'accessibility.chartContainerLabel',
		            {
		                title: stripTags(chartTitle),
		                chart: chart
		            }
		        )
		    );

		    // Set screen reader properties on export menu
		    if (
		        chart.exportSVGElements &&
		        chart.exportSVGElements[0] &&
		        chart.exportSVGElements[0].element
		    ) {
		        // Set event handler on button
		        var button = chart.exportSVGElements[0].element,
		            oldExportCallback = button.onclick;
		        button.onclick = function () {
		            oldExportCallback.apply(
		                this,
		                Array.prototype.slice.call(arguments)
		            );
		            chart.addAccessibleContextMenuAttribs();
		            chart.highlightExportItem(0);
		        };

		        // Set props on button
		        button.setAttribute('role', 'button');
		        button.setAttribute(
		            'aria-label',
		            chart.langFormat(
		                'accessibility.exporting.menuButtonLabel', { chart: chart }
		            )
		        );

		        // Set props on group
		        chart.exportingGroup.element.setAttribute('role', 'region');
		        chart.exportingGroup.element.setAttribute('aria-label',
		            chart.langFormat(
		                'accessibility.exporting.exportRegionLabel', { chart: chart }
		            )
		        );
		    }

		    // 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',
		                    chart.langFormat(
		                        'accessibility.rangeSelector' +
		                            (i ? 'MaxInput' : 'MinInput'), { chart: chart }
		                    )
		                );
		            }
		        });
		    }

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

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

		    // Add ID and summary attr 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="' + chart.langFormat(
		                    'accessibility.tableSummary', { chart: chart }
		                ) + '">'
		            );
		    });
		});

	}(Highcharts));
	(function (H) {
		/**
		 * Accessibility module - Keyboard navigation
		 *
		 * (c) 2010-2017 Highsoft AS
		 * Author: Oystein Moseng
		 *
		 * License: www.highcharts.com/license
		 */


		var win = H.win,
		    doc = win.document,
		    each = H.each,
		    addEvent = H.addEvent,
		    fireEvent = H.fireEvent,
		    merge = H.merge,
		    pick = H.pick,
		    hasSVGFocusSupport;

		// Add focus border functionality to SVGElements.
		// Draws a new rect on top of element around its bounding box.
		H.extend(H.SVGElement.prototype, {
		    addFocusBorder: function (margin, style) {
		        // Allow updating by just adding new border
		        if (this.focusBorder) {
		            this.removeFocusBorder();
		        }
		        // Add the border rect
		        var bb = this.getBBox(),
		            pad = pick(margin, 3);
		        this.focusBorder = this.renderer.rect(
		            bb.x - pad,
		            bb.y - pad,
		            bb.width + 2 * pad,
		            bb.height + 2 * pad,
		            style && style.borderRadius
		        )
		        .addClass('highcharts-focus-border')
        
		        .attr({
		            stroke: style && style.stroke,
		            'stroke-width': style && style.strokeWidth
		        })
        
		        .attr({
		            zIndex: 99
		        })
		        .add(this.parentGroup);
		    },

		    removeFocusBorder: function () {
		        if (this.focusBorder) {
		            this.focusBorder.destroy();
		            delete this.focusBorder;
		        }
		    }
		});


		// Set for which series types it makes sense to move to the closest point with
		// up/down arrows, and which series types should just move to next series.
		H.Series.prototype.keyboardMoveVertical = true;
		each(['column', 'pie'], function (type) {
		    if (H.seriesTypes[type]) {
		        H.seriesTypes[type].prototype.keyboardMoveVertical = false;
		    }
		});


		/**
		 * Strip HTML tags away from a string. Used for aria-label attributes, painting
		 * on a canvas will fail if the text contains tags.
		 * @param  {String} s The input string
		 * @return {String}   The filtered string
		 */
		function stripTags(s) {
		    return typeof s === 'string' ? s.replace(/<\/?[^>]+(>|$)/g, '') : s;
		}


		/**
		 * Set default keyboard navigation options
		 */
		H.setOptions({
		    accessibility: {

		        /**
		         * Options for keyboard navigation.
		         *
		         * @type      {Object}
		         * @since     5.0.0
		         * @apioption accessibility.keyboardNavigation
		         */
		        keyboardNavigation: {

		            /**
		             * Enable keyboard navigation for the chart.
		             *
		             * @type      {Boolean}
		             * @default   true
		             * @since     5.0.0
		             * @apioption accessibility.keyboardNavigation.enabled
		             */
		            enabled: true,


		            /**
		             * Options for the focus border drawn around elements while
		             * navigating through them.
		             *
		             * @type      {Object}
		             * @sample    highcharts/accessibility/custom-focus
		             *            Custom focus ring
		             * @since     6.0.3
		             * @apioption accessibility.keyboardNavigation.focusBorder
		             */
		            focusBorder: {
		                /**
		                 * Enable/disable focus border for chart.
		                 *
		                 * @type      {Boolean}
		                 * @default   true
		                 * @since     6.0.3
		                 * @apioption accessibility.keyboardNavigation.focusBorder.enabled
		                 */
		                enabled: true,

		                /**
		                 * Hide the browser's default focus indicator.
		                 *
		                 * @type      {Boolean}
		                 * @default   true
		                 * @since     6.0.4
		                 * @apioption accessibility.keyboardNavigation.focusBorder.hideBrowserFocusOutline
		                 */
		                hideBrowserFocusOutline: true,

		                /**
		                 * Style options for the focus border drawn around elements
		                 * while navigating through them. Note that some browsers in
		                 * addition draw their own borders for focused elements. These
		                 * automatic borders can not be styled by Highcharts.
		                 *
		                 * In styled mode, the border is given the
		                 * `.highcharts-focus-border` class.
		                 *
		                 * @type      {Object}
		                 * @since     6.0.3
		                 * @apioption accessibility.keyboardNavigation.focusBorder.style
		                 */
		                style: {
		                    /**
		                     * Color of the focus border.
		                     *
		                     * @type      {Color}
		                     * @default   #000000
		                     * @since     6.0.3
		                     * @apioption accessibility.keyboardNavigation.focusBorder.style.color
		                    */
		                    color: '#335cad',
		                    /**
		                     * Line width of the focus border.
		                     *
		                     * @type      {Number}
		                     * @default   2
		                     * @since     6.0.3
		                     * @apioption accessibility.keyboardNavigation.focusBorder.style.lineWidth
		                    */
		                    lineWidth: 2,
		                    /**
		                     * Border radius of the focus border.
		                     *
		                     * @type      {Number}
		                     * @default   3
		                     * @since     6.0.3
		                     * @apioption accessibility.keyboardNavigation.focusBorder.style.borderRadius
		                    */
		                    borderRadius: 3
		                },

		                /**
		                 * Focus border margin around the elements.
		                 *
		                 * @type      {Number}
		                 * @default   2
		                 * @since     6.0.3
		                 * @apioption accessibility.keyboardNavigation.focusBorder.margin
		                 */
		                margin: 2
		            },

		            /**
		             * Set the keyboard navigation mode for the chart. Can be "normal"
		             * or "serialize". In normal mode, left/right arrow keys move
		             * between points in a series, while up/down arrow keys move between
		             * series. Up/down navigation acts intelligently to figure out which
		             * series makes sense to move to from any given point.
		             *
		             * In "serialize" mode, points are instead navigated as a single
		             * list. Left/right behaves as in "normal" mode. Up/down arrow keys
		             * will behave like left/right. This is useful for unifying
		             * navigation behavior with/without screen readers enabled.
		             *
		             * @type      {String}
		             * @validvalue ["normal", "serialize"]
		             * @default   normal
		             * @since     6.0.4
		             * @apioption accessibility.keyboardNavigation.mode
		             */

		            /**
		             * Skip null points when navigating through points with the
		             * keyboard.
		             *
		             * @type      {Boolean}
		             * @default   true
		             * @since     5.0.0
		             * @apioption accessibility.keyboardNavigation.skipNullPoints
		             */
		            skipNullPoints: true
		        }
		    }
		});

		/**
		 * Keyboard navigation for the legend. Requires the Accessibility module.
		 * @since 5.0.14
		 * @apioption legend.keyboardNavigation
		 */

		/**
		 * Enable/disable keyboard navigation for the legend. Requires the Accessibility
		 * module.
		 *
		 * @type {Boolean}
		 * @see [accessibility.keyboardNavigation](
		 *      #accessibility.keyboardNavigation.enabled)
		 * @default true
		 * @since 5.0.13
		 * @apioption legend.keyboardNavigation.enabled
		 */


		// 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. Terminate holds a function to run
		// once before moving to next/prev module.
		// The chart object keeps track of a list of KeyboardNavigationModules.
		function KeyboardNavigationModule(chart, options) {
		    this.chart = chart;
		    this.id = options.id;
		    this.keyCodeMap = options.keyCodeMap;
		    this.validate = options.validate;
		    this.init = options.init;
		    this.terminate = options.terminate;
		}
		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,
		            found = false,
		            handled = false;
		        each(this.keyCodeMap, function (codeSet) {
		            if (codeSet[0].indexOf(keyCode) > -1) {
		                found = true;
		                handled = codeSet[1].call(navModule, keyCode, e) === false ?
		                    // If explicitly returning false, we haven't handled it
		                    false :
		                    true;
		            }
		        });
		        // Default tab handler, move to next/prev module
		        if (!found && keyCode === 9) {
		            handled = this.move(e.shiftKey ? -1 : 1);
		        }
		        return handled;
		    },

		    // 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) {
		        var chart = this.chart;
		        if (this.terminate) {
		            this.terminate(direction);
		        }
		        chart.keyboardNavigationModuleIndex += direction;
		        var newModule = chart.keyboardNavigationModules[
		            chart.keyboardNavigationModuleIndex
		        ];

		        // Remove existing focus border if any
		        if (chart.focusElement) {
		            chart.focusElement.removeFocusBorder();
		        }

		        // Verify new module
		        if (newModule) {
		            if (newModule.validate && !newModule.validate()) {
		                return this.move(direction); // Invalid module, recurse
		            }
		            if (newModule.init) {
		                newModule.init(direction); // Valid module, init it
		                return true;
		            }
		        }
		        // No module
		        chart.keyboardNavigationModuleIndex = 0; // Reset counter

		        // Set focus to chart or exit anchor depending on direction
		        if (direction > 0) {
		            this.chart.exiting = true;
		            this.chart.tabExitAnchor.focus();
		        } else {
		            this.chart.renderTo.focus();
		        }

		        return false;
		    }
		};


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


		// Determine if a point should be skipped
		function isSkipPoint(point) {
		    var a11yOptions = point.series.chart.options.accessibility;
		    return point.isNull && a11yOptions.keyboardNavigation.skipNullPoints ||
		        point.series.options.skipKeyboardNavigation ||
		        !point.series.visible ||
		        point.visible === false ||
		        // Skip all points in a series where pointDescriptionThreshold is
		        // reached
		        (a11yOptions.pointDescriptionThreshold &&
		        a11yOptions.pointDescriptionThreshold <= point.series.points.length);
		}


		// Get the point in a series that is closest (in distance) to a reference point
		// Optionally supply weight factors for x and y directions
		function getClosestPoint(point, series, xWeight, yWeight) {
		    var minDistance = Infinity,
		        dPoint,
		        minIx,
		        distance,
		        i = series.points.length;
		    if (point.plotX === undefined || point.plotY === undefined) {
		        return;
		    }
		    while (i--) {
		        dPoint = series.points[i];
		        if (dPoint.plotX === undefined || dPoint.plotY === undefined) {
		            continue;
		        }
		        distance = (point.plotX - dPoint.plotX) *
		                (point.plotX - dPoint.plotX) * (xWeight || 1) +
		                (point.plotY - dPoint.plotY) *
		                (point.plotY - dPoint.plotY) * (yWeight || 1);
		        if (distance < minDistance) {
		            minDistance = distance;
		            minIx = i;
		        }
		    }
		    return minIx !== undefined && series.points[minIx];
		}


		// 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);
		};


		// Set chart's focus to an SVGElement. Calls focus() on it, and draws the focus
		// border. If the focusElement argument is supplied, it draws the border around
		// svgElement and sets the focus to focusElement.
		H.Chart.prototype.setFocusToElement = function (svgElement, focusElement) {
		    var focusBorderOptions = this.options.accessibility
		                .keyboardNavigation.focusBorder,
		        browserFocusElement = focusElement || svgElement;
		    // Set browser focus if possible
		    if (
		        browserFocusElement.element &&
		        browserFocusElement.element.focus
		    ) {
		        browserFocusElement.element.focus();
		        // Hide default focus ring
		        if (focusBorderOptions.hideBrowserFocusOutline) {
		            browserFocusElement.css({ outline: 'none' });
		        }
		    }
		    if (focusBorderOptions.enabled) {
		        // Remove old focus border
		        if (this.focusElement) {
		            this.focusElement.removeFocusBorder();
		        }
		        // Draw focus border (since some browsers don't do it automatically)
		        svgElement.addFocusBorder(focusBorderOptions.margin, {
		            stroke: focusBorderOptions.style.color,
		            strokeWidth: focusBorderOptions.style.lineWidth,
		            borderRadius: focusBorderOptions.style.borderRadius
		        });
		        this.focusElement = svgElement;
		    }
		};


		// 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.isNull) {
		        this.onMouseOver(); // Show the hover marker and tooltip
		    } else {
		        if (chart.tooltip) {
		            chart.tooltip.hide(0);
		        }
		        // Don't call blur on the element, as it messes up the chart div's focus
		    }

		    // We focus only after calling onMouseOver because the state change can
		    // change z-index and mess up the element.
		    if (this.graphic) {
		        chart.setFocusToElement(this.graphic);
		    }

		    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 chart = this,
		        series = chart.series,
		        curPoint = chart.highlightedPoint,
		        curPointIndex = curPoint && curPoint.index || 0,
		        curPoints = curPoint && curPoint.series.points,
		        lastSeries = chart.series && chart.series[chart.series.length - 1],
		        lastPoint = lastSeries && lastSeries.points &&
		                    lastSeries.points[lastSeries.points.length - 1],
		        newSeries,
		        newPoint;

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

		    if (!curPoint) {
		        // No point is highlighted yet. Try first/last point depending on move
		        // direction
		        newPoint = next ? series[0].points[0] : lastPoint;
		    } else {
		        // We have a highlighted point.
		        // Find index of current point in series.points array. Necessary for
		        // dataGrouping (and maybe zoom?)
		        if (curPoints[curPointIndex] !== curPoint) {
		            for (var i = 0; i < curPoints.length; ++i) {
		                if (curPoints[i] === curPoint) {
		                    curPointIndex = i;
		                    break;
		                }
		            }
		        }

		        // Grab next/prev point & series
		        newSeries = series[curPoint.series.index + (next ? 1 : -1)];
		        newPoint = curPoints[curPointIndex + (next ? 1 : -1)] ||
		                    // Done with this series, try next one
		                    newSeries &&
		                    newSeries.points[next ? 0 : newSeries.points.length - 1];

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

		    // Recursively skip null points or points in series that should be skipped
		    if (isSkipPoint(newPoint)) {
		        chart.highlightedPoint = newPoint;
		        return chart.highlightAdjacentPoint(next);
		    }

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


		// Highlight first valid point in a series. Returns the point if successfully
		// highlighted, otherwise false. If there is a highlighted point in the series,
		// use that as starting point.
		H.Series.prototype.highlightFirstValidPoint = function () {
		    var curPoint = this.chart.highlightedPoint,
		        start = (curPoint && curPoint.series) === this ? curPoint.index : 0,
		        points = this.points;

		    if (points) {
		        for (var i = start, len = points.length; i < len; ++i) {
		            if (!isSkipPoint(points[i])) {
		                return points[i].highlight();
		            }
		        }
		        for (var j = start; j >= 0; --j) {
		            if (!isSkipPoint(points[j])) {
		                return points[j].highlight();
		            }
		        }
		    }
		    return false;
		};


		// Highlight next/previous series in chart. Returns false if no adjacent series
		// in the direction, otherwise returns new highlighted point.
		H.Chart.prototype.highlightAdjacentSeries = function (down) {
		    var chart = this,
		        newSeries,
		        newPoint,
		        adjacentNewPoint,
		        curPoint = chart.highlightedPoint,
		        lastSeries = chart.series && chart.series[chart.series.length - 1],
		        lastPoint = lastSeries && lastSeries.points &&
		                    lastSeries.points[lastSeries.points.length - 1];

		    // If no point is highlighted, highlight the first/last point
		    if (!chart.highlightedPoint) {
		        newSeries = down ? (chart.series && chart.series[0]) : lastSeries;
		        newPoint = down ?
		            (newSeries && newSeries.points && newSeries.points[0]) : lastPoint;
		        return newPoint ? newPoint.highlight() : false;
		    }

		    newSeries = chart.series[curPoint.series.index + (down ? -1 : 1)];

		    if (!newSeries) {
		        return false;
		    }

		    // We have a new series in this direction, find the right point
		    // Weigh xDistance as counting much higher than Y distance
		    newPoint = getClosestPoint(curPoint, newSeries, 4);

		    if (!newPoint) {
		        return false;
		    }

		    // New series and point exists, but we might want to skip it
		    if (!newSeries.visible) {
		        // Skip the series
		        newPoint.highlight();
		        adjacentNewPoint = chart.highlightAdjacentSeries(down); // Try recurse
		        if (!adjacentNewPoint) {
		            // Recurse failed
		            curPoint.highlight();
		            return false;
		        }
		        // Recurse succeeded
		        return adjacentNewPoint;
		    }

		    // Highlight the new point or any first valid point back or forwards from it
		    newPoint.highlight();
		    return newPoint.series.highlightFirstValidPoint();
		};


		// Highlight the closest point vertically
		H.Chart.prototype.highlightAdjacentPointVertical = function (down) {
		    var curPoint = this.highlightedPoint,
		        minDistance = Infinity,
		        bestPoint;

		    if (curPoint.plotX === undefined || curPoint.plotY === undefined) {
		        return false;
		    }
		    each(this.series, function (series) {
		        each(series.points, function (point) {
		            if (point.plotY === undefined || point.plotX === undefined ||
		                point === curPoint) {
		                return;
		            }
		            var yDistance = point.plotY - curPoint.plotY,
		                width = Math.abs(point.plotX - curPoint.plotX),
		                distance = Math.abs(yDistance) * Math.abs(yDistance) +
		                    width * width * 4; // Weigh horizontal distance highly

		            // Reverse distance number if axis is reversed
		            if (series.yAxis.reversed) {
		                yDistance *= -1;
		            }

		            if (
		                yDistance < 0 && down || yDistance > 0 && !down || // Wrong dir
		                distance < 5 || // Points in same spot => infinite loop
		                isSkipPoint(point)
		            ) {
		                return;
		            }

		            if (distance < minDistance) {
		                minDistance = distance;
		                bestPoint = point;
		            }
		        });
		    });

		    return bestPoint ? bestPoint.highlight() : false;
		};


		// 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);
		    }
		};


		// 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;
		        if (hasSVGFocusSupport) {
		            // Only focus if we can set focus back to the elements after
		            // destroying the menu (#7422)
		            this.renderTo.focus();
		        }
		    }
		};


		// 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 && hasSVGFocusSupport) {
		            // Only focus if we can set focus back to the elements after
		            // destroying the menu (#7422)
		            listItem.focus();
		        }
		        if (curHighlighted && curHighlighted.onmouseout) {
		            curHighlighted.onmouseout();
		        }
		        if (listItem.onmouseover) {
		            listItem.onmouseover();
		        }
		        this.highlightedExportItem = ix;
		        return true;
		    }
		};


		// Try to highlight the last valid export menu item
		H.Chart.prototype.highlightLastExportItem = function () {
		    var chart = this,
		        i;
		    if (chart.exportDivElements) {
		        i = chart.exportDivElements.length;
		        while (i--) {
		            if (chart.highlightExportItem(i)) {
		                break;
		            }
		        }
		    }
		};


		// 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]) {
		        this.setFocusToElement(buttons[ix].box, buttons[ix]);
		        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,
		        oldIx = this.highlightedLegendItemIx;
		    if (items[ix]) {
		        if (items[oldIx]) {
		            fireEvent(
		                items[oldIx].legendGroup.element,
		                'mouseout'
		            );
		        }
		        // Scroll if we have to
		        if (items[ix].pageIx !== undefined &&
		            items[ix].pageIx + 1 !== this.legend.currentPage) {
		            this.legend.scroll(1 + items[ix].pageIx - this.legend.currentPage);
		        }
		        // Focus
		        this.highlightedLegendItemIx = ix;
		        this.setFocusToElement(items[ix].legendItem, items[ix].legendGroup);
		        fireEvent(items[ix].legendGroup.element, 'mouseover');
		        return true;
		    }
		    return false;
		};


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

		    function navModuleFactory(id, keyMap, options) {
		        return new KeyboardNavigationModule(chart, merge({
		            keyCodeMap: keyMap
		        }, { id: id }, options));
		    }

		    // 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 = [
		        // Entry point catching the first tab, allowing users to tab into points
		        // more intuitively.
		        navModuleFactory('entry', []),

		        // Points
		        navModuleFactory('points', [
		            // Left/Right
		            [[37, 39], function (keyCode) {
		                var right = keyCode === 39;
		                if (!chart.highlightAdjacentPoint(right)) {
		                    // Failed to highlight next, wrap to last/first
		                    return this.init(right ? 1 : -1);
		                }
		                return true;
		            }],
		            // Up/Down
		            [[38, 40], function (keyCode) {
		                var down = keyCode !== 38,
		                    navOptions = chart.options.accessibility.keyboardNavigation;
		                if (navOptions.mode && navOptions.mode === 'serialize') {
		                    // Act like left/right
		                    if (!chart.highlightAdjacentPoint(down)) {
		                        return this.init(down ? 1 : -1);
		                    }
		                    return true;
		                }
		                // Normal mode, move between series
		                var highlightMethod = chart.highlightedPoint &&
		                        chart.highlightedPoint.series.keyboardMoveVertical ?
		                        'highlightAdjacentPointVertical' :
		                        'highlightAdjacentSeries';
		                chart[highlightMethod](down);
		                return true;
		            }],
		            // Enter/Spacebar
		            [[13, 32], function () {
		                if (chart.highlightedPoint) {
		                    chart.highlightedPoint.firePointEvent('click');
		                }
		            }]
		        ], {
		            // Always start highlighting from scratch when entering this module
		            init: function (dir) {
		                var numSeries = chart.series.length,
		                    i = dir > 0 ? 0 : numSeries,
		                    res;
		                if (dir > 0) {
		                    delete chart.highlightedPoint;
		                    // Find first valid point to highlight
		                    while (i < numSeries) {
		                        res = chart.series[i].highlightFirstValidPoint();
		                        if (res) {
		                            return res;
		                        }
		                        ++i;
		                    }
		                } else {
		                    // Find last valid point to highlight
		                    while (i--) {
		                        chart.highlightedPoint = chart.series[i].points[
		                            chart.series[i].points.length - 1
		                        ];
		                        // Highlight first valid point in the series will also
		                        // look backwards. It always starts from currently
		                        // highlighted point.
		                        res = chart.series[i].highlightFirstValidPoint();
		                        if (res) {
		                            return res;
		                        }
		                    }
		                }
		            },
		            // If leaving points, don't show tooltip anymore
		            terminate: function () {
		                if (chart.tooltip) {
		                    chart.tooltip.hide(0);
		                }
		                delete chart.highlightedPoint;
		            }
		        }),

		        // Exporting
		        navModuleFactory('exporting', [
		            // Left/Up
		            [[37, 38], function () {
		                var i = chart.highlightedExportItem || 0,
		                    reachedEnd = true;
		                // 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.highlightLastExportItem();
		                    return true;
		                }
		            }],
		            // 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.highlightExportItem(0);
		                    return true;
		                }
		            }],
		            // 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.highlightLastExportItem();
		                }
		            },
		            // Hide the menu
		            terminate: function () {
		                chart.hideExportMenu();
		            }
		        }),

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

		            // 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',
		                        chart.langFormat(
		                            'accessibility.mapZoom' + (i ? 'Out' : 'In'),
		                            { chart: chart }
		                        )
		                    );
		                });

		                chart.setFocusToElement(initialButton.box, initialButton);
		                initialButton.setState(2);
		                chart.focusedMapNavButtonIx = direction > 0 ? 0 : 1;
		            }
		        }),

		        // Highstock range selector (minus input boxes)
		        navModuleFactory('rangeSelector', [
		            // 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 () {
		                // Don't allow click if button used to be disabled
		                if (chart.oldRangeSelectorItemState !== 3) {
		                    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',
		                        chart.langFormat(
		                            'accessibility.rangeSelectorButton',
		                            {
		                                chart: chart,
		                                buttonText: 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('rangeSelectorInput', [
		            // 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();
		            }]
		        ], {
		            // 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
		                );
		            },

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

		        // Legend navigation
		        navModuleFactory('legend', [
		            // 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
		                ) && chart.legend.allItems.length > 1) {
		                    // Wrap around if more than 1 item
		                    this.init(direction);
		                }
		            }],
		            // Enter/Spacebar
		            [[13, 32], function () {
		                var legendElement = chart.legend.allItems[
		                        chart.highlightedLegendItemIx
		                    ].legendItem.element;
		                fakeClickEvent(
		                     !chart.legend.options.useHTML ? // #8561
		                        legendElement.parentNode : legendElement
		                );
		            }]
		        ], {
		            // Only run this module if we have at least one legend - wait for
		            // it - item. Don't run if the legend is populated by a colorAxis.
		            // Don't run if legend navigation is disabled.
		            validate: function () {
		                return chart.legend && chart.legend.allItems &&
		                    chart.legend.display &&
		                    !(chart.colorAxis && chart.colorAxis.length) &&
		                    (chart.options.legend &&
		                    chart.options.legend.keyboardNavigation &&
		                    chart.options.legend.keyboardNavigation.enabled) !== false;
		            },

		            // 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',
		                        chart.langFormat(
		                            'accessibility.legendItem',
		                            {
		                                chart: chart,
		                                itemName: stripTags(item.name)
		                            }
		                        )
		                    );
		                });
		                // Focus first/last item
		                chart.highlightLegendItem(
		                    direction > 0 ? 0 : chart.legend.allItems.length - 1
		                );
		            }
		        })
		    ];
		};


		// Add exit anchor to the chart
		// We use this to move focus out of chart whenever we want, by setting focus
		// to this div and not preventing the default tab action.
		// We also use this when users come back into the chart by tabbing back, in
		// order to navigate from the end of the chart.
		// Function returns the unbind function for the exit anchor's event handler.
		H.Chart.prototype.addExitAnchor = function () {
		    var chart = this;
		    chart.tabExitAnchor = doc.createElement('div');
		    chart.tabExitAnchor.setAttribute('tabindex', '0');

		    // Hide exit anchor
		    merge(true, chart.tabExitAnchor.style, {
		        position: 'absolute',
		        left: '-9999px',
		        top: 'auto',
		        width: '1px',
		        height: '1px',
		        overflow: 'hidden'
		    });

		    chart.renderTo.appendChild(chart.tabExitAnchor);
		    return addEvent(chart.tabExitAnchor, 'focus',
		        function (ev) {
		            var e = ev || win.event,
		                curModule;

		            // If focusing and we are exiting, do nothing once.
		            if (!chart.exiting) {

		                // Not exiting, means we are coming in backwards
		                chart.renderTo.focus();
		                e.preventDefault();

		                // Move to last valid keyboard nav module
		                // Note the we don't run it, just set the index
		                chart.keyboardNavigationModuleIndex =
		                    chart.keyboardNavigationModules.length - 1;
		                curModule = chart.keyboardNavigationModules[
		                    chart.keyboardNavigationModuleIndex
		                ];

		                // Validate the module
		                if (curModule.validate && !curModule.validate()) {
		                    // Invalid.
		                    // Move inits next valid module in direction
		                    curModule.move(-1);
		                } else {
		                    // We have a valid module, init it
		                    curModule.init(-1);
		                }

		            } else {
		                // Don't skip the next focus, we only skip once.
		                chart.exiting = false;
		            }
		        }
		    );
		};


		// Clear the chart and reset the navigation state
		H.Chart.prototype.resetKeyboardNavigation = function () {
		    var chart = this,
		        curMod = (
		            chart.keyboardNavigationModules &&
		            chart.keyboardNavigationModules[
		                chart.keyboardNavigationModuleIndex || 0
		            ]
		        );
		    if (curMod && curMod.terminate) {
		        curMod.terminate();
		    }
		    if (chart.focusElement) {
		        chart.focusElement.removeFocusBorder();
		    }
		    chart.keyboardNavigationModuleIndex = 0;
		    chart.keyboardReset = true;
		};


		/**
		 * On destroy, we need to clean up the focus border and the state
		 */
		H.addEvent(H.Series, 'destroy', function () {
		    var chart = this.chart;
		    if (chart.highlightedPoint && chart.highlightedPoint.series === this) {
		        delete chart.highlightedPoint;
		        if (chart.focusElement) {
		            chart.focusElement.removeFocusBorder();
		        }
		    }
		});


		// Add keyboard navigation events on chart load
		H.Chart.prototype.callbacks.push(function (chart) {
		    var a11yOptions = chart.options.accessibility;
		    if (a11yOptions.enabled && a11yOptions.keyboardNavigation.enabled) {

		        // Test if we have focus support for SVG elements
		        hasSVGFocusSupport = !!chart.renderTo
		                                .getElementsByTagName('g')[0].focus;

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

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

		        // Add tab exit anchor
		        if (!chart.tabExitAnchor) {
		            chart.unbindExitAnchorFocus = chart.addExitAnchor();
		        }

		        // Handle keyboard events by routing them to active keyboard nav module
		        chart.unbindKeydownHandler = addEvent(chart.renderTo, 'keydown',
		            function (ev) {
		                var e = ev || win.event,
		                    curNavModule = chart.keyboardNavigationModules[
		                        chart.keyboardNavigationModuleIndex
		                    ];
		                chart.keyboardReset = false;
		                // If there is a nav module for the current index, run it.
		                // Otherwise, we are outside of the chart in some direction.
		                if (curNavModule) {
		                    if (curNavModule.run(e)) {
		                        // Successfully handled this key event, stop default
		                        e.preventDefault();
		                    }
		                }
		            });

		        // Reset chart navigation state if we click outside the chart and it's
		        // not already reset
		        chart.unbindBlurHandler = addEvent(doc, 'mouseup', function () {
		            if (
		                !chart.keyboardReset &&
		                !(chart.pointer && chart.pointer.chartPosition)
		            ) {
		                chart.resetKeyboardNavigation();
		            }
		        });

		        // Add cleanup handlers
		        addEvent(chart, 'destroy', function () {
		            chart.resetKeyboardNavigation();
		            if (chart.unbindExitAnchorFocus && chart.tabExitAnchor) {
		                chart.unbindExitAnchorFocus();
		            }
		            if (chart.unbindKeydownHandler && chart.renderTo) {
		                chart.unbindKeydownHandler();
		            }
		            if (chart.unbindBlurHandler) {
		                chart.unbindBlurHandler();
		            }
		        });
		    }
		});

	}(Highcharts));
	return (function () {


	}());
}));
