color negative columns in Highstock

negative-column.js

(function () {
    var originalGetAttribs = Highcharts.seriesTypes.column.prototype.getAttribs;

    Highcharts.seriesTypes.column.prototype.getAttribs = function () {
        var merge  = Highcharts.merge,
            series = this,
            points = series.points,
            
            stateOptions  = series.options.states,
            negativeColor = series.options.negativeColor,
            threshold     = series.options.negativeThreshold,
            
            i = points.length,
            
            seriesNegativePointAttr;

        // run original method
        originalGetAttribs.call(this);
    
        
        // do a magic stuff
        seriesNegativePointAttr = merge(series.pointAttr);
        seriesNegativePointAttr[''].fill = negativeColor;
        seriesNegativePointAttr.hover.fill = stateOptions.hover.upColor || negativeColor;
        seriesNegativePointAttr.select.fill = stateOptions.select.upColor || negativeColor;
        
        while (i--) {
            if (points[i].y < threshold)
                points[i].pointAttr = seriesNegativePointAttr;
        }
    }
}());