chart.js:将堆叠条形图的工具提示放在条形图顶部

<script src="https://cdn.jsdelivr.net/npm/chart.js"></script>

<canvas id="myChart"></canvas>

var ctx = document.getElementById('myChart').getContext('2d');
var myChart = new Chart(ctx, {
    type: 'bar',
    data: {
        labels: ['数据系列1', '数据系列2', '数据系列3'],
        datasets: [{
            label: '数据系列1',
            data: [10, 20, 30],
            backgroundColor: 'rgba(255, 99, 132, 0.5)'
        }, {
            label: '数据系列2',
            data: [15, 25, 35],
            backgroundColor: 'rgba(54, 162, 235, 0.5)'
        }, {
            label: '数据系列3',
            data: [5, 15, 25],
            backgroundColor: 'rgba(75, 192, 192, 0.5)'
        }]
    },
    options: {
        tooltips: {
            mode: 'index',
            intersect: false,
            position: 'average',
            callbacks: {
                title: function(tooltipItem, data) {
                    return data.labels[tooltipItem[0].index];
                },
                label: function(tooltipItem, data) {
                    var datasetLabel = data.datasets[tooltipItem.datasetIndex].label || '';
                    return datasetLabel + ': ' + tooltipItem.yLabel;
                }
            }
        },
        scales: {
            x: {
                stacked: true
            },
            y: {
                stacked: true
            }
        }
    }
});