score:0

Accepted answer

as mentioned, you should use tooltip.formatter function (http://api.highcharts.com/highcharts#tooltip.formatter). in your case that would be

"formatter": function () {
  return "i'd like to have first yaxis category here<br>" 
    + "<span style=\"font-weight: bold; color:" + this.series.color + "\">"
    + this.series.chart.yaxis[0].categories[this.y] + "</span><br/>"
    + "and second yaxis category here. <br/>"
    + "<span style=\"font-weight: bold; color:" + this.series.color + "\">"
    + this.series.chart.yaxis[1].categories[this.y] + "</span><br/>"
    + "x value: " + this.point.x + "<br/>"
  },

(https://jsfiddle.net/75444q2n/3/)

score:0

you could use tooltip.formatter (api: http://api.highcharts.com/highcharts#tooltip.formatter) and get y of the point to get corresponding category from category array or from chart directly. example: http://jsfiddle.net/4w89vl75/2/

$(function () {
    var cat2 = ['jul', 'aug', 'sep', 'oct', 'nov', 'dec'];
    $('#container').highcharts({
        tooltip: {
            formatter: function () {
                return 'first: ' + this.series.chart.yaxis[0].categories[this.y] +
                    '<br>second: ' + cat2[this.y];
            }
        },

        yaxis: [{
            categories: ['jan', 'feb', 'mar', 'apr','may', 'jun']
        },{
            linkedto: 0,
            opposite: true,
            categories: cat2
        }],

        series: [{
            data: [5,3,2,4,3]
        }, {
            yaxis: 1,
            data: [2,2,3,4,5]
        }]
    });
});

Related Query

More Query from same tag